#include <bits/stdc++.h> using namespace std; 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) {} }; class Solution { public: bool isSameTree(TreeNode *p, TreeNode *q) { if (p == nullptr && q == nullptr) { return true; } if (p == nullptr || q == nullptr) { return false; } if (p->val != q->val) { return false; } return isSameTree(p->left, q->left) && isSameTree(p->right, q->right); } };