Given a binary tree, determine if it is height-balanced. For this
problem, a height-balanced binary tree is defined as a binary tree in
which the depth of the two subtrees of every node never differ by
more than 1.
/**
* 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) {
return solve(root) != -1;
}
int solve(TreeNode *root) {
if (root == NULL) return 0;
int left = solve(root->left);
int right = solve(root->right);
if (left == -1 || right == -1 || abs(left - right) > 1) return -1;
return max(left,right) + 1;
}
};