Add Solution for 100 Same Tree

cpp/100_Same_Tree.cpp

@@ -0,0 +1,52 @@
+// 100. Same Tree
+/**
+ * Given two binary trees, write a function to check if they are equal or not.
+ * 
+ * Two binary trees are considered equal if they are structurally identical and the nodes have the same value.
+ * 
+ * Tags: Tree, Depth-first Search
+ * 
+ * Author: Kuang Qin
+ */
+
+#include <iostream>
+
+using namespace std;
+
+/**
+ * Definition for a binary tree node.
+ */
+struct TreeNode {
+    int val;
+    TreeNode *left;
+    TreeNode *right;
+    TreeNode(int x) : val(x), left(NULL), right(NULL) {}
+    TreeNode(int x, TreeNode *l, TreeNode *r) : val(x), left(l), right(r) {}
+};
+
+class Solution {
+public:
+    bool isSameTree(TreeNode* p, TreeNode* q) {
+        if (p == NULL && q == NULL) {
+            return true;
+        }
+
+        if (p != NULL && q != NULL) {
+            if (p->val == q->val) {
+                return isSameTree(p->left, q->left) && isSameTree(p->right, q->right);
+            }
+        }
+
+        return false;
+    }
+};
+
+int main() {
+    TreeNode node1_1(1), node1_4(4), node1_2(2, &node1_1, NULL), node1_5(5, &node1_4, NULL), node1_3(3, &node1_2, &node1_5);
+    TreeNode node2_1(1), node2_4(4), node2_2(2, &node2_1, NULL), node2_5(5, NULL, &node2_4), node2_3(3, &node2_2, &node2_5);
+    Solution sol;
+    bool ans = sol.isSameTree(&node1_3, &node2_3);
+    cout << ans << endl;
+    cin.get();
+    return 0;
+}