LeetCode:Binary Tree Level Order Traversal Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level). For example:Given binary tree {3,9,20,#,#,15,7}, 3 / \ 9 20 / \ 15 7 return its level ord…

LeetCode: Binary Tree Traversal 题目:树的先序和后序. 后序地址:https://oj.leetcode.com/problems/binary-tree-postorder-traversal/ 先序地址:https://oj.leetcode.com/problems/binary-tree-preorder-traversal/ 后序算法:利用栈的非递归算法.初始时,先从根节点一直往左走到底,并把相应的元素进栈:在循环里每次都取出栈顶元素,如果该栈顶元素的右…

Given a sorted (in ascending order) integer array nums of n elements and a target value, write a function to search target in nums. If target exists, then return its index, otherwise return -1. Example 1: Input: nums = [-1,0,3,5,9,12], target = 9 Out…

LeetCode Binary Search All In One Binary Search 二分查找算法 https://leetcode-cn.com/problems/binary-search/ https://leetcode-cn.com/problems/binary-search/solution/er-fen-cha-zhao-by-leetcode/ 复杂度分析 时间复杂度:\mathcal{O}(\log N)O(logN). 空间复杂度:\mathcal{O}(1)O(…

LeetCode & Binary Search 解题模版 In computer science, binary search, also known as half-interval search, logarithmic search, or binary chop, is a search algorithm that finds the position of a target value within a sorted array. 在计算机科学中,二分搜索(也称为半间隔搜索,对数搜…

A binary watch has 4 LEDs on the top which represent the hours (0-11), and the 6 LEDs on the bottom represent the minutes (0-59). Each LED represents a zero or one, with the least significant bit on the right. For example, the above binary watch read…

Given a binary tree, return the vertical order traversal of its nodes' values. (ie, from top to bottom, column by column). If two nodes are in the same row and column, the order should be from left to right. Examples: Given binary tree [3,9,20,null,n…

Given a binary tree, find the length of the longest consecutive sequence path. The path refers to any sequence of nodes from some starting node to any node in the tree along the parent-child connections. The longest consecutive path need to be from p…

Given a binary tree, return all root-to-leaf paths. For example, given the following binary tree: 1 / \ 2 3 \ 5 All root-to-leaf paths are: ["1->2->5", "1->3"] 这道题给我们一个二叉树,让我们返回所有根到叶节点的路径,跟之前那道Path Sum II 二叉树路径之和之二很类似,比那道稍微简单一…

Given a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom. For example:Given the following binary tree, 1 <--- / \ 2 3 <--- \ \ 5 4 <--- You should return [1, 3,…