/** * Definition for binary tree * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:    int depth(TreeNode *node){        if(node==NULL)            return 0;        int i=depth(node->left);        int j=depth(node->right);        return max(i,j)+1;    }    bool isBalanced(TreeNode *root) {        if(root==NULL)            return true;        int leftDep=depth(root->left);        int rightDep=depth(root->right);        if(abs(leftDep-rightDep)<=1)            return isBalanced(root->left) && isBalanced(root->right);        else            return false;    }};