// Definition for a binary tree node. struct TreeNode { int val; struct TreeNode *left; struct TreeNode *right; }; //深度优先 bool isSameTree(struct TreeNode* p, struct TreeNode* q){ if(p==NULL&&q==NULL) return true; if(p==NULL||q==NULL) return false; if(p->val==q->val) return isSameTree(p->left, q->left) && isSameTree(p->right, q->right); else return false; }