balanced-binary-tree.cpp

/**
 * 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 height(TreeNode*root){
            if(root==NULL){
                return 0;
            }
            int left = height(root->left);
            if(left==-1){
                return -1;
            }
            int right = height(root->right);
            if(right==-1){
                return -1;
            }
            if(abs(right-left)>1)return -1;
            return max(left,right)+1;
        }
    
        bool isBalanced(TreeNode* root) {
            return height(root)!=-1;
        }
    };