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.
把问题分解看，same tree 要求满足 值相等，然后左右子树也是same tree 这题和 balanced tree 相似
1 class Solution { 2 public: 3 bool isSameTree(TreeNode* p, TreeNode* q) { 4 if (p == NULL && q ==NULL) 5 return true; 6 if (p == NULL || q == NULL) 7 return false; 8 return p->val == q->val && isSameTree(p->left,q->left) && isSameTree(p->right,q->right); 9 10 } 11 };
原文：http://www.cnblogs.com/zhuguanyu33/p/4570864.html