leetcode 111 Minimum Depth of Binary Tree(DFS)

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leetcode 111 Minimum Depth of Binary Tree(DFS)

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. 题解:注意没有的分支不算. /** * Definition for a binary tree node. * struct TreeNode { * int val; * Tr…

[LeetCode] 111. Minimum Depth of Binary Tree 二叉树的最小深度

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. 给一个二叉树,找出它的最小深度.最小深度是从根节点向下到最近的叶节点的最短路径,就是最短路径的节点个数. 解法1:DFS 解法2: BFS Java: DFS, Time Comp…

[LeetCode] 111. Minimum Depth of Binary Tree ☆(二叉树的最小深度)

[Leetcode] Maximum and Minimum Depth of Binary Tree 二叉树的最小最大深度 (最小有3种解法) 描述解析递归深度优先搜索当求最大深度时,我们只要在左右子树中取较大的就行了. 然而最小深度时,如果左右子树中有一个为空会返回0,这时我们是不能算做有效深度的. 所以分成了三种情况,左子树为空,右子树为空,左右子树都不为空.当然,如果左右子树都为空的话,就会返回1. 广度优先搜索(类似层序遍历的思想) 递归解法本质是深度优先搜索,但因为我们是求最小…

Leetcode 111 Minimum Depth of Binary Tree 二叉树

找出最短的从叶子到根的路径长可以回忆Maximum Depth of Binary Tree的写法,只不过在!root,我把它改成了10000000,还有max函数改成了min函数,最后的值如果是10000000,毫无疑问这棵树肯定为空,因此在最后有(d>=1000000)?0:d; /** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *righ…

(二叉树 BFS DFS) leetcode 111. 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. Note: A leaf is a node with no children. Example: Given binary tree [3,9,20,null,null,15,7…

leetcode 111 minimum depth of binary tree

problem description: 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. problem analysis: 第一步,设计演算法:遍历一棵树的方法有两种,BFS and DFS,思考了下,BFS是一圈一圈的扩张出…

LeetCode 111. Minimum Depth of Binary Tree （二叉树最小的深度）

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. 题目标题:Tree 这道题目给了我们一个二叉树,让我们找到它最小的深度,注意这里的最小深度是指root 到一个 leaf node. 举个例子: 1 / 2 / 3 这种情况,…

leetcode 111 Minimum Depth of Binary Tree ----- java

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. 求树的最低高度. 没什么技巧性,用队列,遇到叶子结点的时候返回结果. /** * Definition for a binary tree node. * public cl…

Java [Leetcode 111]Minimum Depth of Binary Tree

题目描述: 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. 解题思路: 递归. 代码描述: /** * Definition for a binary tree node. * public class TreeNode { *…

Java for LeetCode 111 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. 解题思路:注意minimum depth最后遍历的那个点,left right都必须为null,JAVA实现如下: public int minDepth(TreeNode roo…