Leetcode: balanced_binary_tree, leetcode

Leetcode: balanced_binary_tree, leetcode

I. Question

Determine whether the given binary tree is a balanced binary tree, that is, the depth difference of each node is not greater than 1

Ii. Analysis

We generally think of recursion for tree problems, and the same is true for this question. We only need to determine whether the left and right subtree of each node are balanced.

Recursion, recursion, recursion ......

 

/** * Definition for binary tree * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:    bool isBalanced(TreeNode *root) {if(depthcheck(root)==0)return true;if(abs(depthcheck(root->left)-depthcheck(root->right))>1)return false;elsereturn isBalanced(root->left) && isBalanced(root->right);} int depthcheck(TreeNode *root){if(!root)return 0;int depthL=depthcheck(root->left)+1;int depthR=depthcheck(root->right)+1;return depthL > depthR ? depthL : depthR;}};

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What is leetcode?

There are many programming and interview questions, which can be compiled and run online. It is difficult. If you can do it all by yourself, it is very helpful for large companies. I just did the questions there.