LeetCode Balanced Binary Tree

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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.

思路：递归判断。

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    private boolean ans;
    private int cal(TreeNode root) {
		if (root == null) return 0;
		if (ans == false) return -1;
		int left = cal(root.left);
		int right = cal(root.right);
		
		if (Math.abs(left - right) > 1) ans = false;
		return Math.max(left, right) + 1;
	}
	
    public boolean isBalanced(TreeNode root) {
    	this.ans = true;
    	cal(root);
    	return ans;
    }
}

LeetCode Balanced Binary Tree

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原文地址：http://blog.csdn.net/u011345136/article/details/45563725