Invert a binary tree. Example: Input: 4 / \ 2 7 / \ / \ 1 3 6 9 Output: 4 / \ 7 2 / \ / \ 9 6 3 1 Trivia:This problem was inspired by this original tweet by Max Howell: Google: 90% of our engineers use the software you wrote (Homebrew), but you can’t…

Problem A tree is a connected graph with no cycles. A rooted tree is a tree in which one special vertex is called the root. If there is an edge between X and Y in a rooted tree, we say that Y is a child of X if X is closer to the root than Y (in othe…

题目 链接:http://code.google.com/codejam/contest/2984486/dashboard#s=p1 googlde code jam 2014 Round1A 解题报告下载 word版 归类 动态规划,DFS 解法1[最优解] 耗时 1秒左右 分析 使用DFS和DP.目前为止的最优方案. 关键是用二维数组children_nodes[1001][1001]来表示父节点下的子节点的个数,例如 children_nodes[4][2]表示当2节点作为4节点的父亲的…

class TreeNode { int val; TreeNode left; TreeNode right; TreeNode(int x) { val = x; } } public class Solution { public boolean isBalanced(TreeNode root) { if(root==null)return true; int left=treeDepth(root.left); int right=treeDepth(root.right); if(M…

题目链接:Balanced Binary Tree | LeetCode OJ 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 tha…

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. 求二叉树是否平衡,根据题目中的定义,高度平衡二叉树是每一个节点的两个字…

问题: 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. 分析: 判断平衡二叉树,第一想法肯定是求出左右子树的深度,看是…

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. Solution:  bool helperBalanced(int…

110.Balanced Binary Tree 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. 很早以前做的了  准…

Minimum Depth of Binary Tree Given a binary tree, find its minimum depth. The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node. 比较左子树和右子树的深度,取小的那个返回上来,并+1. 需要注意的是如果没有左子树或右子树.那么无条件取存在的那一边子树深…