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.
/** * Definition for binary tree * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ struct TreeNode { int val; TreeNode *left; TreeNode *right; TreeNode(int x) : val(x), left(NULL), right(NULL) {} }; class Solution { public: bool isSameTree(TreeNode *p, TreeNode *q) { if(p == NULL && q == NULL) return true; if((p == NULL&&q != NULL)||(p != NULL&&q == NULL)||(p->val != q->val)) return false; return isSameTree(p->left,q->left)&&isSameTree(p->right,q->right); } };