二叉树OJ--3

链接: 单值二叉数

class Solution {
public:bool isUT(TreeNode* root,int c) {if(root==NULL)return 1;if(root->val!=c)return 0;return isUT(root->left,c)&&isUT(root->right,c);}bool isUnivalTree(TreeNode* root) {int c=root->val;return isUT(root,c);}
};

链接: 最大深度

class Solution {
public:int maxDepth(TreeNode* root) {if(root==nullptr){return 0;}if((root->left==nullptr)&&(root->right==nullptr))return 1;auto left=maxDepth(root->left);auto right=maxDepth(root->right);return left>right?left+1:right+1; }
};

链接: 反转二叉树

class Solution {
public:TreeNode* invertTree(TreeNode* root) {if(root==nullptr)return nullptr;std::swap(root->left,root->right);invertTree(root->left);invertTree(root->right);return root;}
};