Refactor structure

include/s0002_add_two_numbers.hpp

@@ -1,13 +1,7 @@
 #ifndef S0002_ADD_TWO_NUMBERS_HPP
 #define S0002_ADD_TWO_NUMBERS_HPP
 
-struct ListNode {
-  int val;
-  ListNode* next;
-  ListNode() : val(0), next(nullptr) {}
-  ListNode(int x) : val(x), next(nullptr) {}
-  ListNode(int x, ListNode* next) : val(x), next(next) {}
-};
+#include "structures.hpp"
 
 class S0002 {
  public:

include/s0019_remove_nth_node_from_end_of_list.hpp

@@ -1,13 +1,7 @@
 #ifndef S0019_REMOVE_NTH_NODE_FROM_END_OF_LIST_HPP
 #define S0019_REMOVE_NTH_NODE_FROM_END_OF_LIST_HPP
 
-struct ListNode {
-  int val;
-  ListNode* next;
-  ListNode() : val(0), next(nullptr) {}
-  ListNode(int x) : val(x), next(nullptr) {}
-  ListNode(int x, ListNode* next) : val(x), next(next) {}
-};
+#include "structures.hpp"
 
 class S0019 {
  public:

include/s0021_merge_two_sorted_lists.hpp

@@ -3,15 +3,9 @@
 
 #include <limits>
 
-using namespace std;
+#include "structures.hpp"
 
-struct ListNode {
-  int val;
-  ListNode* next;
-  ListNode() : val(0), next(nullptr) {}
-  ListNode(int x) : val(x), next(nullptr) {}
-  ListNode(int x, ListNode* next) : val(x), next(next) {}
-};
+using namespace std;
 
 class S0021 {
  public:

include/s0023_merge_k_sorted_lists.hpp

@@ -3,15 +3,9 @@
 
 #include <vector>
 
-using namespace std;
+#include "structures.hpp"
 
-struct ListNode {
-  int val;
-  ListNode *next;
-  ListNode() : val(0), next(nullptr) {}
-  ListNode(int x) : val(x), next(nullptr) {}
-  ListNode(int x, ListNode *next) : val(x), next(next) {}
-};
+using namespace std;
 
 class S0023 {
  public:

include/s0024_swap_nodes_in_pairs.hpp

@@ -1,13 +1,7 @@
 #ifndef S0024_SWAP_NODES_IN_PAIRS_HPP
 #define S0024_SWAP_NODES_IN_PAIRS_HPP
 
-struct ListNode {
-  int val;
-  ListNode* next;
-  ListNode() : val(0), next(nullptr) {}
-  ListNode(int x) : val(x), next(nullptr) {}
-  ListNode(int x, ListNode* next) : val(x), next(next) {}
-};
+#include "structures.hpp"
 
 class S0024 {
  public:

include/s0025_reverse_nodes_in_k-group.hpp

@@ -4,15 +4,9 @@
 #include <tuple>
 #include <utility>
 
-using namespace std;
+#include "structures.hpp"
 
-struct ListNode {
-  int val;
-  ListNode* next;
-  ListNode() : val(0), next(nullptr) {}
-  ListNode(int x) : val(x), next(nullptr) {}
-  ListNode(int x, ListNode* next) : val(x), next(next) {}
-};
+using namespace std;
 
 class S0025 {
  public:

include/s0142_linked_list_cycle.hpp

@@ -3,11 +3,7 @@
 
 #include <unordered_map>
 
-struct ListNode {
-  int val;
-  ListNode* next;
-  ListNode(int x) : val(x), next(nullptr) {}
-};
+#include "structures.hpp"
 
 struct IterResult {
   ListNode *node;

include/s0160_intersection_of_two_linked_lists.hpp

@@ -1,11 +1,7 @@
 #ifndef S0160_INTERSECTION_OF_TWO_LINKED_LISTS_HPP
 #define S0160_INTERSECTION_OF_TWO_LINKED_LISTS_HPP
 
-struct ListNode {
-  int val;
-  ListNode *next;
-  ListNode(int x) : val(x), next(nullptr) {}
-};
+#include "structures.hpp"
 
 class S0160 {
  public:

include/s0203_remove_linked_list_elements.hpp

@@ -1,13 +1,7 @@
 #ifndef S0203_REMOVE_LINKED_LIST_ELEMENTS_HPP
 #define S0203_REMOVE_LINKED_LIST_ELEMENTS_HPP
 
-struct ListNode {
-  int val;
-  ListNode* next;
-  ListNode() : val(0), next(nullptr) {}
-  ListNode(int x) : val(x), next(nullptr) {}
-  ListNode(int x, ListNode* next) : val(x), next(next) {}
-};
+#include "structures.hpp"
 
 class S0203 {
  public:

include/s0206_reverse_linked_list.hpp

@@ -1,13 +1,7 @@
 #ifndef S0206_REVERSE_LINKED_LIST_HPP
 #define S0206_REVERSE_LINKED_LIST_HPP
 
-struct ListNode {
-  int val;
-  ListNode* next;
-  ListNode() : val(0), next(nullptr) {}
-  ListNode(int x) : val(x), next(nullptr) {}
-  ListNode(int x, ListNode* next) : val(x), next(next) {}
-};
+#include "structures.hpp"
 
 class S0206 {
  public:

include/s0226_invert_binary_tree.hpp

@@ -0,0 +1,11 @@
+#ifndef S0226_INVERT_BINARY_TREE_HPP
+#define S0226_INVERT_BINARY_TREE_HPP
+
+#include "structures.hpp"
+
+class S0226 {
+ public:
+  TreeNode* invertTree(TreeNode* root);
+};
+
+#endif

include/structures.hpp

@@ -0,0 +1,22 @@
+#ifndef STRUCTURES_HPP
+#define STRUCTURES_HPP
+
+struct ListNode {
+  int val;
+  ListNode *next;
+  ListNode() : val(0), next(nullptr) {}
+  ListNode(int x) : val(x), next(nullptr) {}
+  ListNode(int x, ListNode *next) : val(x), next(next) {}
+};
+
+struct TreeNode {
+  int val;
+  TreeNode *left;
+  TreeNode *right;
+  TreeNode() : val(0), left(nullptr), right(nullptr) {}
+  TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
+  TreeNode(int x, TreeNode *left, TreeNode *right)
+      : val(x), left(left), right(right) {}
+};
+
+#endif