今天太忙了…
一、理论学习
二、刷题学习
104. 二叉树的最大深度
应该确实比以前有提升了 已经能写出这么精简的代码了
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
int maxDepth(TreeNode* root) {
if(root==nullptr) return 0;
return 1+max(maxDepth(root->left),maxDepth(root->right));
}
};
111. 二叉树的最小深度
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
int minDepth(TreeNode* root) {
if (root == NULL) return 0;
if (root->left == NULL && root->right != NULL) {
return 1 + minDepth(root->right);
}
if (root->left != NULL && root->right == NULL) {
return 1 + minDepth(root->left);
}
return 1 + min(minDepth(root->left), minDepth(root->right));
}
};
222. 完全二叉树的节点个数
自己尝试
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
int nums(TreeNode* root,int num){
if(root==nullptr) return 0;
num=num+1;
int left=nums(root->left,num);
int right=nums(root->right,num);
return left+right+1;
}
int countNodes(TreeNode* root) {
return nums(root,0);
}
};
三、新年快乐