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:判断是否是平衡二叉树,dfs即可,递归判断每个子树是否平衡二叉树,如果有子树不满足,则整体也不满足。
具体代码如下:
/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ public class Solution { /** * 判断是否平衡二叉树 * 看左右子树高度差是否超过1 * 不超过1则分别判断左右子树是否平衡二叉树 */ public boolean isBalanced(TreeNode root) { if(root == null) return true; if(dep(0,root) > - 10) return true; return false; } //计算树的高度 private int dep(int dep,TreeNode root){ if(root == null){ return dep-1; } int dep1 = dep(dep+1,root.left); int dep2 = dep(dep+1,root.right); //如果高度差超过1,返回-10 //则以后的dep返回值均为-10 if(Math.abs(dep1 - dep2) > 1){ return -10; } return dep1 > dep2 ? dep1 : dep2; } }
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时间: 2024-10-12 15:08:25