Leetcode#110 Balanced Binary Tree

 1 int balancedp(TreeNode *root) {
 2   if (!root)
 3     return 0;
 4 
 5   int l = balancedp(root->left);
 6   int r = balancedp(root->right);
 7   if ((l | r) < 0 || abs(l - r) > 1)
 8     return -1;
 9   return max(l, r) + 1;
10 }
11 
12 bool isBalanced(TreeNode *root) {
13   return balancedp(root) >= 0;
14 }