s0030

include/s0030_substring_with_concatenation_of_all_words.hpp

@@ -0,0 +1,15 @@
+#ifndef S0030_SUBSTRING_WITH_CONCATENATION_OF_ALL_WORDS
+#define S0030_SUBSTRING_WITH_CONCATENATION_OF_ALL_WORDS
+
+#include <vector>
+#include <string>
+#include <unordered_map>
+
+using namespace std;
+
+class Solution {
+ public:
+  vector<int> findSubstring(string s, vector<string>& words);
+};
+
+#endif

src/s0030_substring_with_concatenation_of_all_words.cpp

@@ -0,0 +1,33 @@
+#include "s0030_substring_with_concatenation_of_all_words.hpp"
+
+vector<int> Solution::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) {
+    unordered_map<string, int> differ;
+    for (int j = 0; j < m; ++j) {
+      ++differ[s.substr(i + j * n, n)];
+    }
+    for (string& word : words) {
+      if (--differ[word] == 0) {
+        differ.erase(word);
+      }
+    }
+    for (int start = i; start < ls - m * n + 1; start += n) {
+      if (start != i) {
+        string word = s.substr(start + (m - 1) * n, n);
+        if (++differ[word] == 0) {
+          differ.erase(word);
+        }
+        word = s.substr(start - n, n);
+        if (--differ[word] == 0) {
+          differ.erase(word);
+        }
+      }
+      if (differ.empty()) {
+        res.emplace_back(start);
+      }
+    }
+  }
+  return res;
+}

tests/s0030_substring_with_concatenation_of_all_words.cpp

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+#include "s0030_substring_with_concatenation_of_all_words.hpp"
+
+#include <gtest/gtest.h>
+
+TEST(Problem30, Case1) {
+  string s{"barfoothefoobarman"};
+  vector<string> words{"foo", "bar"};
+  vector<int> o{0, 9};
+  Solution solution;
+  EXPECT_EQ(solution.findSubstring(s, words), o);
+}
+
+TEST(Problem30, Case2) {
+  string s{"wordgoodgoodgoodbestword"};
+  vector<string> words{"word","good","best","word"};
+  vector<int> o{};
+  Solution solution;
+  EXPECT_EQ(solution.findSubstring(s, words), o);
+}