110. Balanced Binary Tree

Balanced Binary Tree

代码

public class Solution {

private int helper(TreeNode root, int height){
if (root == null)
{
return height;
}

int leftTree = helper(root.left, height + 1);
int rightTree = helper(root.right, height + 1);
if (leftTree < 0 || rightTree < 0 || Math.abs(leftTree - rightTree) > 1)
{
return -1;
}

return Math.max(leftTree, rightTree);
}
public boolean isBalanced(TreeNode root) {
return helper(root, 0) >= 0;
}
}