题解 | #判断是不是平衡二叉树#

using System;
using System.Collections.Generic;

/*
public class TreeNode
{
    public int val;
    public TreeNode left;
    public TreeNode right;

    public TreeNode (int x)
    {
        val = x;
    }
}
*/

class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param pRoot TreeNode类
     * @return bool布尔型
     */
    public bool IsBalanced_Solution(TreeNode pRoot) {
        // write code here
        if (pRoot == null)
            return true;
        bool bL = IsBalanced_Solution(pRoot.left);
        bool bR = IsBalanced_Solution(pRoot.left);
        if (!bL || !bR)
            return false;
        int nL = IBS(pRoot.left);
        int nR = IBS(pRoot.right);
        if (Math.Abs(nL - nR) > 1)
            return false;
        return true;
    }

    public int IBS(TreeNode pRoot) {
        if (pRoot == null)
            return 0;
        int nL = IBS(pRoot.left);
        int nR = IBS(pRoot.right);
        return 1 + (nL > nR ? nL : nR);
    }
}