题目

示例： 

思路分析

代码实现 

bool isUnivalTree(struct TreeNode* root) {if(root==NULL){return true;}if(root->left && root->val != root->left->val){return false;}if(root->right && root->val != root->right->val){return false;}return isUnivalTree(root->left) && isUnivalTree(root->right);
}