Refactor

include/offer_05.hpp

@@ -5,7 +5,7 @@
 
 using namespace std;
 
-class Solution {
+class Offer05 {
  public:
   string replaceSpace(string s);
 };

include/offer_58.hpp

@@ -5,7 +5,7 @@
 
 using namespace std;
 
-class Solution {
+class Offer58 {
  public:
   string reverseLeftWords(string s, int n);
   void reverseSubStr(string &s, int begin, int end);

include/s0001_two_sum.hpp

@@ -5,7 +5,9 @@
 #include <unordered_map>
 #include <vector>
 
-class Solution {
+using namespace std;
+
+class S0001 {
  public:
   /**
    * @brief Two Sum

include/s0002_add_two_numbers.hpp

@@ -9,7 +9,7 @@ struct ListNode {
   ListNode(int x, ListNode* next) : val(x), next(next) {}
 };
 
-class Solution {
+class S0002 {
  public:
   /**
    * @brief Add Two Numbers

include/s0003_longest_substring_without_repeating_characters.hpp

@@ -4,7 +4,9 @@
 #include <map>
 #include <string>
 
-class Solution {
+using namespace std;
+
+class S0003 {
  public:
   /**
    * @brief Longest Substring Without Repeating Characters

include/s0004_median_of_two_sorted_arrays.hpp

@@ -3,7 +3,9 @@
 
 #include <vector>
 
-class Solution {
+using namespace std;
+
+class S0004 {
  public:
   /**
    * @brief Median of Two Sorted Arrays

include/s0005_longest_palindromic_substring.hpp

@@ -1,26 +1,20 @@
 #ifndef S0005_LONGEST_PALINDROMIC_SUBSTRING_HPP
 #define S0005_LONGEST_PALINDROMIC_SUBSTRING_HPP
 
-#include <string>
 #include <algorithm>
+#include <string>
 #include <vector>
 
 using namespace std;
 
-class Solution1 {
- public:
-  /**
-   * @brief Longest Palindromic Substring
-   *
-   * Given a string s, return the longest palindromic substring in s.
-   *
-   * @param s the given string
-   * @return longest palindromic substring
-   */
-  string longestPalindrome(string s);
-};
+typedef struct S0005ResultStruct {
+  int left1;  // 边界情况为长度为 1 的字符时，扩展完成后的左边界
+  int right1;  // 边界情况为长度为 1 的字符时，扩展完成后的右边界
+  int left2;  // 边界情况为长度为 2 的字符串时，扩展完成后的左边界
+  int right2;  // 边界情况为长度为 2 的字符串时，扩展完成后的右边界
+} S0005Result;
 
-class Solution2 {
+class S0005 {
  public:
   /**
    * @brief Longest Palindromic Substring
@@ -30,7 +24,17 @@ class Solution2 {
    * @param s the given string
    * @return longest palindromic substring
    */
-  string longestPalindrome(string s);
+  string longestPalindrome1(string s);
+  /**
+   * @brief Longest Palindromic Substring
+   *
+   * Given a string s, return the longest palindromic substring in s.
+   *
+   * @param s the given string
+   * @return longest palindromic substring
+   */
+  string longestPalindrome2(string s);
+  S0005Result expand(string s, int i);
 };
 
 #endif

include/s0006_zigzag_conversion.hpp

@@ -5,7 +5,7 @@
 
 using namespace std;
 
-class Solution {
+class S0006 {
  public:
   /**
    * @brief Zigzag Conversion

include/s0007_reverse_integer.hpp

@@ -5,7 +5,9 @@
 #include <cmath>
 #include <climits>
 
-class Solution {
+using namespace std;
+
+class S0007 {
 public:
     int reverse(int x);
 };

include/s0008_string_to_integer.hpp

@@ -8,7 +8,7 @@
 
 using namespace std;
 
-class Solution {
+class S0008 {
 public:
     int myAtoi(string s);
 };

include/s0009_palindrome_number.hpp

@@ -6,7 +6,7 @@
 
 using namespace std;
 
-class Solution {
+class S0009 {
  public:
   bool isPalindrome(int x);
 };

include/s0010_regular_expression_matching.hpp

@@ -6,7 +6,7 @@
 
 using namespace std;
 
-class Solution {
+class S0010 {
  public:
   bool isMatch(string s, string p);
 };

include/s0011_container_with_most_water.hpp

@@ -5,7 +5,7 @@
 
 using namespace std;
 
-class Solution {
+class S0011 {
  public:
   int maxArea(vector<int>& height);
 };

include/s0012_integer_to_roman.hpp

@@ -5,7 +5,7 @@
 
 using namespace std;
 
-class Solution {
+class S0012 {
  public:
   string intToRoman(int num);
 };

include/s0013_roman_to_integer.hpp

@@ -6,7 +6,7 @@
 
 using namespace std;
 
-class Solution {
+class S0013 {
  public:
   int romanToInt(string s);
 };

include/s0014_longest_common_prefix.hpp

@@ -6,7 +6,7 @@
 
 using namespace std;
 
-class Solution {
+class S0014 {
  public:
   string longestCommonPrefix(vector<string>& strs);
 };

include/s0015_3sum.hpp

@@ -7,14 +7,10 @@
 
 using namespace std;
 
-class Solution1 {
+class S0015 {
  public:
-  vector<vector<int>> threeSum(vector<int>& nums);
-};
-
-class Solution2 {
- public:
-  vector<vector<int>> threeSum(vector<int>& nums);
+  vector<vector<int>> threeSum1(vector<int>& nums);
+  vector<vector<int>> threeSum2(vector<int>& nums);
 };
 
 #endif

include/s0016_3sum_closest.hpp

@@ -6,7 +6,7 @@
 
 using namespace std;
 
-class Solution {
+class S0016 {
  public:
   int threeSumClosest(vector<int>& nums, int target);
 };

include/s0017_letter_combinations_of_a_phone_number.hpp

@@ -7,7 +7,7 @@
 
 using namespace std;
 
-class Solution {
+class S0017 {
  public:
   vector<string> letterCombinations(string digits);
 };

include/s0018_4sum.hpp

@@ -6,7 +6,7 @@
 
 using namespace std;
 
-class Solution {
+class S0018 {
  public:
   vector<vector<int>> fourSum(vector<int>& nums, int target);
 };

include/s0019_remove_nth_node_from_end_of_list.hpp

@@ -9,7 +9,7 @@ struct ListNode {
   ListNode(int x, ListNode* next) : val(x), next(next) {}
 };
 
-class Solution {
+class S0019 {
  public:
   ListNode* removeNthFromEnd(ListNode* head, int n);
 };

include/s0020_valid_parentheses.hpp

@@ -6,9 +6,10 @@
 
 using namespace std;
 
-class Solution {
+class S0020 {
  public:
   bool isValid(string s);
+  bool match(string s1, string s2);
 };
 
 #endif

include/s0021_merge_two_sorted_lists.hpp

@@ -1,6 +1,10 @@
 #ifndef S0021_MERGE_TWO_SORTED_LISTS_HPP
 #define S0021_MERGE_TWO_SORTED_LISTS_HPP
 
+#include <limits>
+
+using namespace std;
+
 struct ListNode {
   int val;
   ListNode* next;
@@ -9,9 +13,7 @@ struct ListNode {
   ListNode(int x, ListNode* next) : val(x), next(next) {}
 };
 
-#include <limits>
-
-class Solution {
+class S0021 {
  public:
   ListNode* mergeTwoLists(ListNode* list1, ListNode* list2);
 };

include/s0022_generate_parentheses.hpp

@@ -7,9 +7,10 @@
 
 using namespace std;
 
-class Solution {
+class S0022 {
  public:
   vector<string> generateParenthesis(int n);
+  void dfs(string current, int left, int right, vector<string> &result);
 };
 
 #endif

include/s0023_merge_k_sorted_lists.hpp

@@ -7,15 +7,17 @@ using namespace std;
 
 struct ListNode {
   int val;
-  ListNode* next;
+  ListNode *next;
   ListNode() : val(0), next(nullptr) {}
   ListNode(int x) : val(x), next(nullptr) {}
-  ListNode(int x, ListNode* next) : val(x), next(next) {}
+  ListNode(int x, ListNode *next) : val(x), next(next) {}
 };
 
-class Solution {
+class S0023 {
  public:
-  ListNode* mergeKLists(vector<ListNode*>& lists);
+  ListNode *mergeKLists(vector<ListNode *> &lists);
+  ListNode *mergeTwoLists(ListNode *a, ListNode *b);
+  ListNode *merge(vector<ListNode *> &lists, int l, int r);
 };
 
 #endif

include/s0024_swap_nodes_in_pairs.hpp

@@ -9,7 +9,7 @@ struct ListNode {
   ListNode(int x, ListNode* next) : val(x), next(next) {}
 };
 
-class Solution {
+class S0024 {
  public:
   ListNode* swapPairs(ListNode* head);
 };

include/s0025_reverse_nodes_in_k-group.hpp

@@ -1,8 +1,8 @@
 #ifndef S0025_REVERSE_NODES_IN_K_GROUP_HPP
 #define S0025_REVERSE_NODES_IN_K_GROUP_HPP
 
-#include <utility>
 #include <tuple>
+#include <utility>
 
 using namespace std;
 
@@ -14,9 +14,10 @@ struct ListNode {
   ListNode(int x, ListNode* next) : val(x), next(next) {}
 };
 
-class Solution {
+class S0025 {
  public:
   ListNode* reverseKGroup(ListNode* head, int k);
+  pair<ListNode*, ListNode*> myReverse(ListNode* head, ListNode* tail);
 };
 
 #endif

include/s0026_remove_duplicates_from_sorted_array.hpp

@@ -5,7 +5,7 @@
 
 using namespace std;
 
-class Solution {
+class S0026 {
  public:
   int removeDuplicates(vector<int>& nums);
 };

include/s0027_remove_element.hpp

@@ -5,7 +5,7 @@
 
 using namespace std;
 
-class Solution {
+class S0027 {
  public:
   int removeElement(vector<int>& nums, int val);
 };

include/s0028_find_the_index_of_the_first_occurrence_in_a_string.hpp

@@ -5,7 +5,7 @@
 
 using namespace std;
 
-class Solution {
+class S0028 {
  public:
   int strStr(string haystack, string needle);
 };

include/s0029_divide_two_integers.hpp

@@ -3,9 +3,12 @@
 
 #include <climits>
 
-class Solution {
+using namespace std;
+
+class S0029 {
  public:
   int divide(int dividend, int divisor);
+  int div(long a, long b);
 };
 
 #endif

include/s0030_substring_with_concatenation_of_all_words.hpp

@@ -7,7 +7,7 @@
 
 using namespace std;
 
-class Solution {
+class S0030 {
  public:
   vector<int> findSubstring(string s, vector<string>& words);
 };

include/s0031_next_permutation.hpp

@@ -6,7 +6,7 @@
 
 using namespace std;
 
-class Solution {
+class S0031 {
  public:
   void nextPermutation(vector<int>& nums);
 };

include/s0032_longest_valid_parentheses.hpp

@@ -7,7 +7,7 @@
 
 using namespace std;
 
-class Solution {
+class S0032 {
  public:
   int longestValidParentheses(string s);
 };

include/s0033_search_in_rotated_sorted_array.hpp

@@ -6,7 +6,7 @@
 
 using namespace std;
 
-class Solution {
+class S0033 {
  public:
   int search(vector<int>& nums, int target);
 };

include/s0034_find_first_and_last_position_of_element_in_sorted_array.hpp

@@ -5,13 +5,10 @@
 
 using namespace std;
 
-class Solution1 {
+class S0034 {
  public:
-  vector<int> searchRange(vector<int>& nums, int target);
+  vector<int> searchRange1(vector<int>& nums, int target);
+  vector<int> searchRange2(vector<int>& nums, int target);
 };
 
-class Solution2 {
- public:
-  vector<int> searchRange(vector<int>& nums, int target);
-};
 #endif

include/s0035_search_insert_position.hpp

@@ -5,14 +5,10 @@
 
 using namespace std;
 
-class Solution1 {
+class S0035 {
  public:
-  int searchInsert(vector<int>& nums, int target);
-};
-
-class Solution2 {
- public:
-  int searchInsert(vector<int>& nums, int target);
+  int searchInsert1(vector<int>& nums, int target);
+  int searchInsert2(vector<int>& nums, int target);
 };
 
 #endif

include/s0036_valid_sudoku.hpp

@@ -7,7 +7,7 @@
 
 using namespace std;
 
-class Solution {
+class S0036 {
  public:
   bool isValidSudoku(vector<vector<char>>& board);
 };

include/s0037_sudoku_solver.hpp

@@ -1,16 +1,21 @@
 #ifndef S0037_SUDOKU_SOLVER_HPP
 #define S0037_SUDOKU_SOLVER_HPP
 
-#include <vector>
-#include <unordered_map>
-#include <cmath>
 #include <algorithm>
+#include <cmath>
+#include <unordered_map>
+#include <vector>
 
 using namespace std;
 
-class Solution {
+class S0037 {
  public:
-  void solveSudoku(vector<vector<char>>& board);
+  void solveSudoku(vector<vector<char>> &board);
+  bool recusiveSolveSudoku(vector<vector<char>> &board,
+                           vector<unordered_map<char, bool>> &rows,
+                           vector<unordered_map<char, bool>> &cols,
+                           vector<unordered_map<char, bool>> &grids, int row,
+                           int col);
 };
 
 #endif

include/s0038_count_and_say.hpp

@@ -6,7 +6,7 @@
 
 using namespace std;
 
-class Solution {
+class S0038 {
  public:
   string countAndSay(int n);
 };

include/s0039_combination_sum.hpp

@@ -1,15 +1,17 @@
 #ifndef S0039_COMBINATION_SUM_HPP
 #define S0039_COMBINATION_SUM_HPP
 
-#include <vector>
 #include <algorithm>
 #include <iterator>
+#include <vector>
 
 using namespace std;
 
-class Solution {
+class S0039 {
  public:
   vector<vector<int>> combinationSum(vector<int>& candidates, int target);
+  void dfs(vector<int>& candidates, int target, vector<vector<int>>& ans,
+           vector<int>& combine, int idx);
 };
 
 #endif

include/s0076_minimum_window_substring.hpp

@@ -7,7 +7,7 @@
 
 using namespace std;
 
-class Solution {
+class S0076 {
  public:
   string minWindow(string s, string t);
   unordered_map<char, int> ori, cnt;

include/s0151_reverse_words_in_a_string.hpp

@@ -5,7 +5,7 @@
 
 using namespace std;
 
-class Solution {
+class S0151 {
  public:
   void reverseSubStr(string &s, int begin, int end);
   string reverseWords(string s);

include/s0209_minimum_size_subarray_sum.hpp

@@ -6,7 +6,7 @@
 
 using namespace std;
 
-class Solution {
+class S0209 {
  public:
   int minSubArrayLen(int target, vector<int>& nums);
 };

include/s0283_move_zeroes.hpp

@@ -5,7 +5,7 @@
 
 using namespace std;
 
-class Solution {
+class S0283 {
  public:
   void moveZeroes(vector<int>& nums);
 };

include/s0704_binary_search.hpp

@@ -5,14 +5,10 @@
 
 using namespace std;
 
-class Solution1 {
+class S0704 {
  public:
-  int binSearch(vector<int>& nums, int target);
-};
-
-class Solution2 {
- public:
-  int binSearch(vector<int>& nums, int target);
+  int binSearch1(vector<int>& nums, int target);
+  int binSearch2(vector<int>& nums, int target);
 };
 
 #endif

src/offer_05.cpp

@@ -1,6 +1,6 @@
 #include "offer_05.hpp"
 
-string Solution::replaceSpace(string s) {
+string Offer05::replaceSpace(string s) {
   int len = s.length();
   int cnt{0};
   for (int i{0}; i < len; ++i) {

src/offer_58.cpp

@@ -1,6 +1,6 @@
 #include "offer_58.hpp"
 
-void Solution::reverseSubStr(string &s, int begin, int end) {
+void Offer58::reverseSubStr(string &s, int begin, int end) {
   for (; begin < end; ++begin, --end) {
     char tmp = s[begin];
     s[begin] = s[end];
@@ -8,7 +8,7 @@ void Solution::reverseSubStr(string &s, int begin, int end) {
   }
 }
 
-string Solution::reverseLeftWords(string s, int n) {
+string Offer58::reverseLeftWords(string s, int n) {
   int len = s.length();
   reverseSubStr(s, 0, n - 1);
   reverseSubStr(s, n, len - 1);

src/s0001_two_sum.cpp

@@ -1,7 +1,6 @@
 #include "s0001_two_sum.hpp"
-using namespace std;
 
-vector<int> Solution::twoSum(vector<int>& nums, int target) {
+vector<int> S0001::twoSum(vector<int>& nums, int target) {
   unordered_map<int, int> hashtable;
   for (int i = 0; i < nums.size(); ++i) {
     auto it = hashtable.find(target - nums[i]);

src/s0002_add_two_numbers.cpp

@@ -1,6 +1,6 @@
 #include "s0002_add_two_numbers.hpp"
 
-ListNode* Solution::addTwoNumbers(ListNode* l1, ListNode* l2) {
+ListNode* S0002::addTwoNumbers(ListNode* l1, ListNode* l2) {
   ListNode *l_begin = new ListNode((l1->val + l2->val) % 10);
   ListNode *l_end = l_begin;
   int carry{ (l1->val + l2->val) >= 10 ? 1 : 0 };

src/s0003_longest_substring_without_repeating_characters.cpp

@@ -1,6 +1,6 @@
 #include "s0003_longest_substring_without_repeating_characters.hpp"
 
-int Solution::lengthOfLongestSubstring(std::string s) {
+int S0003::lengthOfLongestSubstring(std::string s) {
   // index_forward points to the frontmost element
   // index_backward points to the last repeated element
   //

src/s0004_median_of_two_sorted_arrays.cpp

@@ -1,6 +1,6 @@
 #include "s0004_median_of_two_sorted_arrays.hpp"
 
-int Solution::getKthElement(const std::vector<int>& nums1,
+int S0004::getKthElement(const std::vector<int>& nums1,
                             const std::vector<int>& nums2, int k) {
   int m = nums1.size();
   int n = nums2.size();
@@ -33,7 +33,7 @@ int Solution::getKthElement(const std::vector<int>& nums1,
   }
 }
 
-double Solution::findMedianSortedArrays(std::vector<int>& nums1,
+double S0004::findMedianSortedArrays(std::vector<int>& nums1,
                                         std::vector<int>& nums2) {
   int totalLength = nums1.size() + nums2.size();
   if (totalLength % 2 == 1) {

src/s0005_longest_palindromic_substring.cpp

@@ -17,7 +17,7 @@
 // 把 dp 这张二维数组的表全部填好，然后在里面找最长的子字符串。
 // 时间复杂度：O(n^2) 因为总共有 n^2 个状态，计算每个状态需要的时间为 O(1)
 // 空间复杂度：O(n^2) 因为总共需要存储 n^2 个状态。
-string Solution1::longestPalindrome(string s) {
+string S0005::longestPalindrome1(string s) {
   int len = s.length();
   vector<vector<int>> dp(len, vector<int>(len));
 
@@ -79,20 +79,13 @@ string Solution1::longestPalindrome(string s) {
 // “回文中心”实际上是两种边界情况，也就是说每个可能的结果都是由边界情况扩展开来的
 // 因此我们可以遍历每个边界情况，对它进行扩展
 
-typedef struct ResultStruct {
-  int left1;  // 边界情况为长度为 1 的字符时，扩展完成后的左边界
-  int right1;  // 边界情况为长度为 1 的字符时，扩展完成后的右边界
-  int left2;  // 边界情况为长度为 2 的字符串时，扩展完成后的左边界
-  int right2;  // 边界情况为长度为 2 的字符串时，扩展完成后的右边界
-} Result;
-
 // 输入为字符串和边界情况的那一点
 // 返回值包含为扩展的结果
-Result expand(string s, int i) {
+S0005Result S0005::expand(string s, int i) {
   int len = s.length();
 
   if (i == len - 1) {
-    return Result{i, i, i, i};
+    return S0005Result{i, i, i, i};
   }
 
   // 边界情况为长度为 1 的字符时
@@ -117,13 +110,13 @@ Result expand(string s, int i) {
     }
   }
 
-  return Result{left1, right1, left2, right2};
+  return S0005Result{left1, right1, left2, right2};
 }
 
-string Solution2::longestPalindrome(string s) {
+string S0005::longestPalindrome2(string s) {
   int len = s.length();
   int left = 0, right = 0;
-  Result result{0, 0, 0, 0};
+  S0005Result result{0, 0, 0, 0};
   for (int i = 0; i < len; i++) {
     result = expand(s, i);
     if (result.right1 - result.left1 > right - left) {

src/s0006_zigzag_conversion.cpp

@@ -13,7 +13,7 @@
 // 2 4   8 10       2*(n-1)*col+row, 2*(n-1)*col-row
 // 3     9          2*(n-1)*col + (n-1)
 
-string Solution::convert(string s, int numRows) {
+string S0006::convert(string s, int numRows) {
   string r = "";
   int l = s.length();
   if (l == 1 || numRows == 1) {

src/s0007_reverse_integer.cpp

@@ -1,6 +1,6 @@
 #include "s0007_reverse_integer.hpp"
 
-int Solution::reverse(int x) {
+int S0007::reverse(int x) {
   int r{0};
   std::queue<int> queue;
 

src/s0008_string_to_integer.cpp

@@ -2,7 +2,7 @@
 
 // 当流程很复杂的时候，画流程图: https://paste.sainnhe.dev/NQxx.png
 
-class Automaton {
+class S0008Automaton {
   string state = "start";
   unordered_map<string, vector<string>> table = {
       {"start", {"start", "signed", "in_number", "end"}},
@@ -32,8 +32,8 @@ class Automaton {
   }
 };
 
-int Solution::myAtoi(string str) {
-  Automaton automaton;
+int S0008::myAtoi(string str) {
+  S0008Automaton automaton;
   for (char c : str) automaton.get(c);
   return automaton.sign * automaton.ans;
 }

src/s0009_palindrome_number.cpp

@@ -1,6 +1,6 @@
 #include "s0009_palindrome_number.hpp"
 
-bool Solution::isPalindrome(int x) {
+bool S0009::isPalindrome(int x) {
   string s = to_string(x);
   string r = s;
   reverse(r.begin(), r.end());

src/s0010_regular_expression_matching.cpp

@@ -3,7 +3,7 @@
 // 动态规划
 // 当前匹配成功 == 之前匹配成功 && 当前字符匹配成功
 
-bool Solution::isMatch(string s, string p) {
+bool S0010::isMatch(string s, string p) {
   int m = s.size();
   int n = p.size();
 

src/s0011_container_with_most_water.cpp

@@ -9,7 +9,7 @@
 //   也就是说只有当移动小的指针时才有可能让储存的水量超过之前的
 // 因此每次迭代我们移动较小的指针，然后统计出最大的储存水量
 
-int Solution::maxArea(vector<int>& height) {
+int S0011::maxArea(vector<int>& height) {
   int max{0};
   for (int l{0}, r{static_cast<int>(height.size() - 1)}; r != l;) {
     if (height.at(l) > height.at(r)) {

src/s0012_integer_to_roman.cpp

@@ -4,7 +4,7 @@
 // 先硬编码一个哈希表
 // 然后当数值大于一个值的时候，就直接把对应的字符串加上去
 
-string Solution::intToRoman(int num) {
+string S0012::intToRoman(int num) {
   int values[] = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1};
   string reps[] = {"M",  "CM", "D",  "CD", "C",  "XC", "L",
                    "XL", "X",  "IX", "V",  "IV", "I"};

src/s0013_roman_to_integer.cpp

@@ -1,6 +1,6 @@
 #include "s0013_roman_to_integer.hpp"
 
-int Solution::romanToInt(string s) {
+int S0013::romanToInt(string s) {
   unordered_map<string, int> map;
   map["I"] = 1;
   map["V"] = 5;

src/s0014_longest_common_prefix.cpp

@@ -1,6 +1,6 @@
 #include "s0014_longest_common_prefix.hpp"
 
-string Solution::longestCommonPrefix(vector<string>& strs) {
+string S0014::longestCommonPrefix(vector<string>& strs) {
   string o{""};
   int size = strs.size();
   int minLen = strs.at(0).length();

src/s0015_3sum.cpp

@@ -6,7 +6,7 @@
 // 去重的方式：
 // 对于每个找到的序列，先排序，如果不存在则添加到结果中。
 
-vector<vector<int>> Solution1::threeSum(vector<int>& nums) {
+vector<vector<int>> S0015::threeSum1(vector<int>& nums) {
   unordered_map<int, int> map;
   vector<vector<int>> result;
   int len = nums.size();
@@ -42,7 +42,7 @@ vector<vector<int>> Solution1::threeSum(vector<int>& nums) {
 
 // 思路二：双指针
 // 先对整个数组排序，然后固定一个数 a ，然后 b, c 从两边往中间靠。
-vector<vector<int>> Solution2::threeSum(vector<int>& nums) {
+vector<vector<int>> S0015::threeSum2(vector<int>& nums) {
   int n = nums.size();
   sort(nums.begin(), nums.end());
   vector<vector<int>> ans;

src/s0016_3sum_closest.cpp

@@ -2,7 +2,7 @@
 
 // 和上一道一样，排序 + 双指针
 
-int Solution::threeSumClosest(vector<int>& nums, int target) {
+int S0016::threeSumClosest(vector<int>& nums, int target) {
   int sum = nums[0] + nums[1] + nums[2];
   int len = nums.size();
   sort(nums.begin(), nums.end());

src/s0017_letter_combinations_of_a_phone_number.cpp

@@ -1,6 +1,6 @@
 #include "s0017_letter_combinations_of_a_phone_number.hpp"
 
-vector<string> Solution::letterCombinations(string digits) {
+vector<string> S0017::letterCombinations(string digits) {
   unordered_map<string, vector<string>> map;
   map["2"] = vector<string>{"a", "b", "c"};
   map["3"] = vector<string>{"d", "e", "f"};

src/s0018_4sum.cpp

@@ -1,6 +1,6 @@
 #include "s0018_4sum.hpp"
 
-vector<vector<int>> Solution::fourSum(vector<int>& nums, int target) {
+vector<vector<int>> S0018::fourSum(vector<int>& nums, int target) {
   int len = nums.size();
   if (len < 4) {
     return {};

src/s0019_remove_nth_node_from_end_of_list.cpp

@@ -6,7 +6,7 @@
 // 步，等快指针走到头时，慢指针指向的的就是倒数第 n 个
 
 // 双指针实现
-ListNode* Solution::removeNthFromEnd(ListNode* head, int n) {
+ListNode* S0019::removeNthFromEnd(ListNode* head, int n) {
   // 一种常见的处理头指针的方法是添加一个哑指针，这个哑指针指向头指针
   // 这样我们就不需要单独讨论头指针了。
   ListNode dummy(0, head);

src/s0020_valid_parentheses.cpp

@@ -1,6 +1,6 @@
 #include "s0020_valid_parentheses.hpp"
 
-bool match(string s1, string s2) {
+bool S0020::match(string s1, string s2) {
   return s1 == "(" && s2 == ")" ||
          s1 == "[" && s2 == "]" ||
          s1 == "{" && s2 == "}";
@@ -8,7 +8,7 @@ bool match(string s1, string s2) {
 
 // 直接用栈
 
-bool Solution::isValid(string s) {
+bool S0020::isValid(string s) {
   stack<string> stack;
   int len = s.length();
   for (int i{0}; i < len; i++) {

src/s0021_merge_two_sorted_lists.cpp

@@ -1,6 +1,6 @@
 #include "s0021_merge_two_sorted_lists.hpp"
 
-ListNode* Solution::mergeTwoLists(ListNode* list1, ListNode* list2) {
+ListNode* S0021::mergeTwoLists(ListNode* list1, ListNode* list2) {
   if (list1 == nullptr) {
     return list2;
   } else if (list2 == nullptr) {

src/s0022_generate_parentheses.cpp

@@ -3,7 +3,7 @@
 // 深度优先遍历:
 // 接收参数为每个节点的状态
 // 遍历结果可以用指针放在接收参数保存，也可以通过声明一个 class 的成员来保存
-void dfs(string current, int left, int right, vector<string> &result) {
+void S0022::dfs(string current, int left, int right, vector<string> &result) {
   // 讨论边界条件（结束条件）
   // 不必讨论起始条件，因为初始化的工作会在 dfs 函数外完成。
   if (left == 0 && right == 0) {
@@ -22,7 +22,7 @@ void dfs(string current, int left, int right, vector<string> &result) {
   }
 }
 
-vector<string> Solution::generateParenthesis(int n) {
+vector<string> S0022::generateParenthesis(int n) {
   // 初始化
   vector<string> result = {};
   dfs("", n, n, result);

src/s0023_merge_k_sorted_lists.cpp

@@ -1,6 +1,6 @@
 #include "s0023_merge_k_sorted_lists.hpp"
 
-ListNode *mergeTwoLists(ListNode *a, ListNode *b) {
+ListNode *S0023::mergeTwoLists(ListNode *a, ListNode *b) {
   if (a == nullptr) {
     return b;
   } else if (b == nullptr) {
@@ -27,7 +27,7 @@ ListNode *mergeTwoLists(ListNode *a, ListNode *b) {
 }
 
 // 分治合并
-ListNode *merge(vector<ListNode*> &lists, int l, int r) {
+ListNode *S0023::merge(vector<ListNode *> &lists, int l, int r) {
   if (l == r) {
     return lists[l];
   }
@@ -38,6 +38,6 @@ ListNode *merge(vector<ListNode*> &lists, int l, int r) {
   return mergeTwoLists(merge(lists, 1, mid), merge(lists, mid + 1, r));
 }
 
-ListNode* Solution::mergeKLists(vector<ListNode*>& lists) {
+ListNode *S0023::mergeKLists(vector<ListNode *> &lists) {
   return merge(lists, 0, lists.size() - 1);
 }

src/s0024_swap_nodes_in_pairs.cpp

@@ -1,6 +1,6 @@
 #include "s0024_swap_nodes_in_pairs.hpp"
 
-ListNode* swapPairs(ListNode* head) {
+ListNode* S0024::swapPairs(ListNode* head) {
   if (head == nullptr || head->next == nullptr) {
     return head;
   }

src/s0025_reverse_nodes_in_k-group.cpp

@@ -1,7 +1,7 @@
 #include "s0025_reverse_nodes_in_k-group.hpp"
 
 // 翻转一个子链表，并且返回新的头与尾
-pair<ListNode*, ListNode*> myReverse(ListNode* head, ListNode* tail) {
+pair<ListNode*, ListNode*> S0025::myReverse(ListNode* head, ListNode* tail) {
   ListNode* prev = tail->next;
   ListNode* p = head;
   while (prev != tail) {
@@ -13,7 +13,7 @@ pair<ListNode*, ListNode*> myReverse(ListNode* head, ListNode* tail) {
   return {tail, head};
 }
 
-ListNode* Solution::reverseKGroup(ListNode* head, int k) {
+ListNode* S0025::reverseKGroup(ListNode* head, int k) {
   ListNode* hair = new ListNode(0);
   hair->next = head;
   ListNode* pre = hair;

src/s0026_remove_duplicates_from_sorted_array.cpp

@@ -1,6 +1,6 @@
 #include "s0026_remove_duplicates_from_sorted_array.hpp"
 
-int Solution::removeDuplicates(vector<int>& nums) {
+int S0026::removeDuplicates(vector<int>& nums) {
   int size = nums.size();
   if (size == 0 || size == 1) {
     return size;

src/s0027_remove_element.cpp

@@ -1,6 +1,6 @@
 #include "s0027_remove_element.hpp"
 
-int Solution::removeElement(vector<int>& nums, int val) {
+int S0027::removeElement(vector<int>& nums, int val) {
   int len = nums.size();
   int f{0}, s{0};
   while (f < len) {

src/s0028_find_the_index_of_the_first_occurrence_in_a_string.cpp

@@ -1,6 +1,6 @@
 #include "s0028_find_the_index_of_the_first_occurrence_in_a_string.hpp"
 
-int Solution::strStr(string haystack, string needle) {
+int S0028::strStr(string haystack, string needle) {
   int haystackLen = haystack.length();
   int needleLen = needle.length();
   for (int i{0}; i < haystackLen; ++i) {

src/s0029_divide_two_integers.cpp

@@ -4,7 +4,7 @@
 // 首先11比3大，结果至少是1，
 // 然后我让3翻倍，就是6，发现11比3翻倍后还要大，那么结果就至少是2了，那我让这个6再翻倍，得12，11不比12大，吓死我了，差点让就让刚才的最小解2也翻倍得到4了。但是我知道最终结果肯定在2和4之间。也就是说2再加上某个数，这个数是多少呢？我让11减去刚才最后一次的结果6，剩下5，我们计算5是3的几倍，也就是除法，看，递归出现了。
 
-int div(long a, long b) {  // 似乎精髓和难点就在于下面这几句
+int S0029::div(long a, long b) {  // 似乎精髓和难点就在于下面这几句
   if (a < b) return 0;
   long count = 1;
   long tb = b;  // 在后面的代码中不更新b
@@ -15,7 +15,7 @@ int div(long a, long b) {  // 似乎精髓和难点就在于下面这几句
   return count + div(a - tb, b);
 }
 
-int Solution::divide(int dividend, int divisor) {
+int S0029::divide(int dividend, int divisor) {
   if (dividend == 0) return 0;
   if (divisor == 1) return dividend;
   if (divisor == -1) {

src/s0030_substring_with_concatenation_of_all_words.cpp

@@ -1,6 +1,6 @@
 #include "s0030_substring_with_concatenation_of_all_words.hpp"
 
-vector<int> Solution::findSubstring(string s, vector<string>& words) {
+vector<int> S0030::findSubstring(string s, vector<string>& words) {
   vector<int> res;
   int m = words.size(), n = words[0].size(), ls = s.size();
   for (int i = 0; i < n && i + m * n <= ls; ++i) {

src/s0031_next_permutation.cpp

@@ -1,6 +1,6 @@
 #include "s0031_next_permutation.hpp"
 
-void Solution::nextPermutation(vector<int>& nums) {
+void S0031::nextPermutation(vector<int>& nums) {
   int i = nums.size() - 2;
   while (i >= 0 && nums[i] >= nums[i + 1]) {
     i--;

src/s0032_longest_valid_parentheses.cpp

@@ -1,6 +1,6 @@
 #include "s0032_longest_valid_parentheses.hpp"
 
-int Solution::longestValidParentheses(string s) {
+int S0032::longestValidParentheses(string s) {
   int maxans = 0, n = s.length();
   vector<int> dp(n, 0);
   for (int i = 1; i < n; i++) {

src/s0033_search_in_rotated_sorted_array.cpp

@@ -5,7 +5,7 @@
 // 思路很简单，对数组二分，有一半一定是有序的，另一半可能有序可能无序
 // 对有序的一半进行二分搜索，无序的部分再次进行二分，如此迭代
 
-int Solution::search(vector<int>& nums, int target) {
+int S0033::search(vector<int>& nums, int target) {
   int size = nums.size();
   int left{0};
   int right = size - 1;

src/s0034_find_first_and_last_position_of_element_in_sorted_array.cpp

@@ -1,8 +1,8 @@
 #include "s0034_find_first_and_last_position_of_element_in_sorted_array.hpp"
 
 // 闭区间写法
-vector<int> Solution1::searchRange(vector<int>& nums, int target) {
-  int len  = nums.size();
+vector<int> S0034::searchRange1(vector<int>& nums, int target) {
+  int len = nums.size();
   int l{0};
   int r = len - 1;
   while (l <= r) {
@@ -27,15 +27,15 @@ vector<int> Solution1::searchRange(vector<int>& nums, int target) {
           break;
         }
       }
-      return vector<int> {l + 1, r - 1};
+      return vector<int>{l + 1, r - 1};
     }
   }
-  return vector<int> {-1, -1};
+  return vector<int>{-1, -1};
 }
 
 // 开区间写法
-vector<int> Solution2::searchRange(vector<int>& nums, int target) {
-  int len  = nums.size();
+vector<int> S0034::searchRange2(vector<int>& nums, int target) {
+  int len = nums.size();
   int l{0};
   int r = len;
   while (l < r) {
@@ -60,8 +60,8 @@ vector<int> Solution2::searchRange(vector<int>& nums, int target) {
           break;
         }
       }
-      return vector<int> {l + 1, r - 1};
+      return vector<int>{l + 1, r - 1};
     }
   }
-  return vector<int> {-1, -1};
+  return vector<int>{-1, -1};
 }

src/s0035_search_insert_position.cpp

@@ -1,7 +1,7 @@
 #include "s0035_search_insert_position.hpp"
 
 // 闭区间写法
-int Solution1::searchInsert(vector<int>& nums, int target) {
+int S0035::searchInsert1(vector<int>& nums, int target) {
   int len = nums.size();
   int l{0};
   int r = len - 1;
@@ -19,7 +19,7 @@ int Solution1::searchInsert(vector<int>& nums, int target) {
 }
 
 // 开区间写法
-int Solution2::searchInsert(vector<int>& nums, int target) {
+int S0035::searchInsert2(vector<int>& nums, int target) {
   int len = nums.size();
   int l{0};
   int r = len;

src/s0036_valid_sudoku.cpp

@@ -1,6 +1,6 @@
 #include "s0036_valid_sudoku.hpp"
 
-bool Solution::isValidSudoku(vector<vector<char>>& board) {
+bool S0036::isValidSudoku(vector<vector<char>>& board) {
   vector<unordered_map<char, int>> rows;
   vector<unordered_map<char, int>> columns;
   vector<unordered_map<char, int>> grids;

src/s0037_sudoku_solver.cpp

@@ -1,11 +1,11 @@
 #include "s0037_sudoku_solver.hpp"
 
 // 返回结果为当前传递进去的数独是否存在解
-bool recusiveSolveSudoku(vector<vector<char>> &board,
-                         vector<unordered_map<char, bool>> &rows,
-                         vector<unordered_map<char, bool>> &cols,
-                         vector<unordered_map<char, bool>> &grids, int row,
-                         int col) {
+bool S0037::recusiveSolveSudoku(vector<vector<char>> &board,
+                                vector<unordered_map<char, bool>> &rows,
+                                vector<unordered_map<char, bool>> &cols,
+                                vector<unordered_map<char, bool>> &grids,
+                                int row, int col) {
   int size = board.size();
   // 边界校验
   if (col == size) {
@@ -49,7 +49,7 @@ bool recusiveSolveSudoku(vector<vector<char>> &board,
   return false;
 }
 
-void Solution::solveSudoku(vector<vector<char>> &board) {
+void S0037::solveSudoku(vector<vector<char>> &board) {
   // 每个行/列/单元格中某个数字是否出现过
   vector<unordered_map<char, bool>> rows;
   vector<unordered_map<char, bool>> cols;

src/s0038_count_and_say.cpp

@@ -1,6 +1,6 @@
 #include "s0038_count_and_say.hpp"
 
-string Solution::countAndSay(int n) {
+string S0038::countAndSay(int n) {
   if (n == 1) {
     return "1";
   } else if (n <= 0) {

src/s0039_combination_sum.cpp

@@ -1,7 +1,7 @@
 #include "s0039_combination_sum.hpp"
 
-void dfs(vector<int>& candidates, int target, vector<vector<int>>& ans,
-         vector<int>& combine, int idx) {
+void S0039::dfs(vector<int>& candidates, int target, vector<vector<int>>& ans,
+                vector<int>& combine, int idx) {
   if (idx == candidates.size()) {
     return;
   }
@@ -19,8 +19,7 @@ void dfs(vector<int>& candidates, int target, vector<vector<int>>& ans,
   }
 }
 
-vector<vector<int>> Solution::combinationSum(vector<int>& candidates,
-                                             int target) {
+vector<vector<int>> S0039::combinationSum(vector<int>& candidates, int target) {
   vector<vector<int>> ans;
   vector<int> combine;
   dfs(candidates, target, ans, combine, 0);

src/s0076_minimum_window_substring.cpp

@@ -1,6 +1,6 @@
 #include "s0076_minimum_window_substring.hpp"
 
-bool Solution::check() {
+bool S0076::check() {
   for (const auto &p : ori) {
     if (cnt[p.first] < p.second) {
       return false;
@@ -11,7 +11,7 @@ bool Solution::check() {
 
 // 不包含 t 中所有字符，r 右移
 // 包含 t 中所有字符，l 右移
-string Solution::minWindow(string s, string t) {
+string S0076::minWindow(string s, string t) {
   for (const auto &c : t) {
     ++ori[c];
   }

src/s0151_reverse_words_in_a_string.cpp

@@ -1,6 +1,14 @@
 #include "s0151_reverse_words_in_a_string.hpp"
 
-string Solution::reverseWords(string s) {
+void S0151::reverseSubStr(string &s, int begin, int end) {
+  for (; begin < end; ++begin, --end) {
+    char tmp = s[begin];
+    s[begin] = s[end];
+    s[end] = tmp;
+  }
+}
+
+string S0151::reverseWords(string s) {
   if (s.length() == 0) {
     return s;
   }

src/s0209_minimum_size_subarray_sum.cpp

@@ -1,6 +1,6 @@
 #include "s0209_minimum_size_subarray_sum.hpp"
 
-int Solution::minSubArrayLen(int target, vector<int>& nums) {
+int S0209::minSubArrayLen(int target, vector<int>& nums) {
   int len = nums.size();
   int result{INT_MAX};
   for (int begin{0}, end{0}, sum{0}; end < len; ++end) {

src/s0283_move_zeroes.cpp

@@ -1,6 +1,6 @@
 #include "s0283_move_zeroes.hpp"
 
-void Solution::moveZeroes(vector<int>& nums) {
+void S0283::moveZeroes(vector<int>& nums) {
   int len = nums.size();
   if (len <= 1) {
     return;

src/s0704_binary_search.cpp

@@ -1,7 +1,7 @@
 #include "s0704_binary_search.hpp"
 
 // 闭区间写法
-int Solution1::binSearch(vector<int>& nums, int target) {
+int S0704::binSearch1(vector<int>& nums, int target) {
   int len = nums.size();
   int l{0};
   int r = len - 1;
@@ -19,7 +19,7 @@ int Solution1::binSearch(vector<int>& nums, int target) {
 }
 
 // 开区间写法
-int Solution2::binSearch(vector<int>& nums, int target) {
+int S0704::binSearch2(vector<int>& nums, int target) {
   int len = nums.size();
   int l{0};
   int r = len;

tests/offer_05.cpp

@@ -5,6 +5,6 @@
 TEST(Offer05, Case1) {
   string s{"We are happy."};
   string expected{"We%20are%20happy."};
-  Solution solution;
+  Offer05 solution;
   EXPECT_EQ(solution.replaceSpace(s), expected);
 }

tests/offer_58.cpp

@@ -6,7 +6,7 @@ TEST(Offer58, Case1) {
   string s{"abcdefg"};
   int k{2};
   string expected{"cdefgab"};
-  Solution solution;
+  Offer58 solution;
   EXPECT_EQ(solution.reverseLeftWords(s, k), expected);
 }
 
@@ -14,6 +14,6 @@ TEST(Offer58, Case2) {
   string s{"lrloseumgh"};
   int k{6};
   string expected{"umghlrlose"};
-  Solution solution;
+  Offer58 solution;
   EXPECT_EQ(solution.reverseLeftWords(s, k), expected);
 }

tests/s0001_two_sum.cpp

@@ -6,7 +6,7 @@
 TEST(Problem1, Case1) {
   std::vector<int> input1{ 2, 7, 11, 15 };
   int input2{ 9 };
-  Solution solution;
+  S0001 solution;
   std::vector<int> result = solution.twoSum(input1, input2);
   std::vector<int> answer = std::vector<int>{ 0, 1 };
   EXPECT_EQ(result, answer);
@@ -15,7 +15,7 @@ TEST(Problem1, Case1) {
 TEST(Problem1, Case2) {
   std::vector<int> input1{ 3, 2, 4 };
   int input2{ 6 };
-  Solution solution;
+  S0001 solution;
   std::vector<int> result = solution.twoSum(input1, input2);
   std::vector<int> answer = std::vector<int>{ 1, 2 };
   EXPECT_EQ(result, answer);
@@ -24,7 +24,7 @@ TEST(Problem1, Case2) {
 TEST(Problem1, Case3) {
   std::vector<int> input1{ 3, 3 };
   int input2{ 6 };
-  Solution solution;
+  S0001 solution;
   std::vector<int> result = solution.twoSum(input1, input2);
   std::vector<int> answer = std::vector<int>{ 0, 1 };
   EXPECT_EQ(result, answer);

tests/s0002_add_two_numbers.cpp

@@ -11,7 +11,7 @@ TEST(Problem2, Case1) {
     new ListNode(5,
         new ListNode(6,
           new ListNode(4)));
-  Solution solution;
+  S0002 solution;
   ListNode *l = solution.addTwoNumbers(l1, l2);
   EXPECT_EQ(l->val, 7);
   EXPECT_EQ(l->next->val, 0);
@@ -21,7 +21,7 @@ TEST(Problem2, Case1) {
 TEST(Problem2, Case2) {
   ListNode *l1 = new ListNode(0);
   ListNode *l2 = new ListNode(0);
-  Solution solution;
+  S0002 solution;
   ListNode *l = solution.addTwoNumbers(l1, l2);
   EXPECT_EQ(l->val, 0);
 }
@@ -40,7 +40,7 @@ TEST(Problem2, Case3) {
         new ListNode(9,
           new ListNode(9,
             new ListNode(9))));
-  Solution solution;
+  S0002 solution;
   ListNode *l = solution.addTwoNumbers(l1, l2);
   EXPECT_EQ(l->val, 8);
   EXPECT_EQ(l->next->val, 9);

tests/s0003_longest_substring_without_repeating_characters.cpp

@@ -4,18 +4,18 @@
 
 TEST(Problem3, Case1) {
   std::string s{std::string("abcabcbb")};
-  Solution solution;
+  S0003 solution;
   EXPECT_EQ(solution.lengthOfLongestSubstring(s), 3);
 }
 
 TEST(Problem3, Case2) {
   std::string s{std::string("bbbbb")};
-  Solution solution;
+  S0003 solution;
   EXPECT_EQ(solution.lengthOfLongestSubstring(s), 1);
 }
 
 TEST(Problem3, Case3) {
   std::string s{std::string("pwwkew")};
-  Solution solution;
+  S0003 solution;
   EXPECT_EQ(solution.lengthOfLongestSubstring(s), 3);
 }

tests/s0004_median_of_two_sorted_arrays.cpp

@@ -6,7 +6,7 @@ TEST(Problem4, Case1) {
   std::vector<int> nums1{1, 3};
   std::vector<int> nums2{2};
   double answer{2};
-  Solution solution;
+  S0004 solution;
   EXPECT_EQ(solution.findMedianSortedArrays(nums1, nums2), answer);
 }
 
@@ -14,6 +14,6 @@ TEST(Problem4, Case2) {
   std::vector<int> nums1{1, 2};
   std::vector<int> nums2{3, 4};
   double answer{2.5};
-  Solution solution;
+  S0004 solution;
   EXPECT_EQ(solution.findMedianSortedArrays(nums1, nums2), answer);
 }

tests/s0005_longest_palindromic_substring.cpp

@@ -6,17 +6,15 @@ TEST(Problem5, Case1) {
   std::string s("babad");
   std::string r1("bab");
   std::string r2("aba");
-  Solution1 solution1;
-  Solution2 solution2;
-  EXPECT_TRUE(solution1.longestPalindrome(s) == r1 || solution1.longestPalindrome(s) == r2);
-  EXPECT_TRUE(solution2.longestPalindrome(s) == r1 || solution2.longestPalindrome(s) == r2);
+  S0005 solution;
+  EXPECT_TRUE(solution.longestPalindrome1(s) == r1 || solution.longestPalindrome1(s) == r2);
+  EXPECT_TRUE(solution.longestPalindrome2(s) == r1 || solution.longestPalindrome2(s) == r2);
 }
 
 TEST(Problem5, Case2) {
   std::string s("cbbd");
   std::string r("bb");
-  Solution1 solution1;
-  Solution2 solution2;
-  EXPECT_EQ(r.compare(solution1.longestPalindrome(s)), 0);
-  EXPECT_EQ(r.compare(solution2.longestPalindrome(s)), 0);
+  S0005 solution;
+  EXPECT_EQ(r.compare(solution.longestPalindrome1(s)), 0);
+  EXPECT_EQ(r.compare(solution.longestPalindrome2(s)), 0);
 }

tests/s0006_zigzag_conversion.cpp

@@ -6,7 +6,7 @@ TEST(Problem6, Case1) {
   string s("PAYPALISHIRING");
   int rows = 3;
   string r("PAHNAPLSIIGYIR");
-  Solution solution;
+  S0006 solution;
   EXPECT_TRUE(solution.convert(s, rows) == r);
 }
 
@@ -14,7 +14,7 @@ TEST(Problem6, Case2) {
   string s("PAYPALISHIRING");
   int rows = 4;
   string r("PINALSIGYAHRPI");
-  Solution solution;
+  S0006 solution;
   EXPECT_TRUE(solution.convert(s, rows) == r);
 }
 
@@ -22,6 +22,6 @@ TEST(Problem6, Case3) {
   string s("AB");
   int rows = 4;
   string r("AB");
-  Solution solution;
+  S0006 solution;
   EXPECT_TRUE(solution.convert(s, rows) == r);
 }