自从做完leetcode上的三道关于二分查找的题后,我觉得它是比链表找环还恶心的题,首先能写出bugfree代码的人就不多,而且可以有各种变形,适合面试的时候不断挑战面试者,一个程序猿写代码解决问题的能力都能在这个过程中考察出来. 在有序数组中寻找等于target的数的下标,没有的情况返回应该插入的下标位置 :http://oj.leetcode.com/problems/search-insert-position/ public int searchInsert(int[] A, int t…

https://oj.leetcode.com/problems/search-for-a-range/就是一个二分查找,没事练练手 public class Solution { public int[] searchRange(int[] A, int target) { int a[]=new int[2]; int ans=bSearch(A,target); if(ans==-1) { a[0]=-1; a[1]=-1; return a; } else { int beg=ans;…

Search for a Range 1.最简单的想法,用最普通的二分查找,找到target,然后向左右扩张,大量的重复的target,就会出现O(n)效率. class Solution { public int[] searchRange(int[] A, int target) { ]; int a= bserch(A,target); ) {ans[]=-;ans[]=-; return ans;} //left ; &&A[b]==target) b--; ans[]=b+; b…

Search in Rotated Sorted Array II Total Accepted: 18500 Total Submissions: 59945My Submissions Follow up for "Search in Rotated Sorted Array": What if duplicates are allowed? Would this affect the run-time complexity? How and why? Write a functi…

本文为senlie原创,转载请保留此地址:http://blog.csdn.net/zhengsenlie Search Insert Position Total Accepted: 14279 Total Submissions: 41575 Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be i…

Search in Rotated Sorted Array Total Accepted: 28132 Total Submissions: 98526My Submissions Suppose a sorted array is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2). You are given a target value to s…

模板 #2: int binarySearch(vector<int>& nums, int target){ if(nums.size() == 0) return -1; int left = 0, right = nums.size(); while(left < right){ // Prevent (left + right) overflow int mid = left + (right - left) / 2; if(nums[mid] == target){ r…

模板 #1: int binarySearch(vector<int>& nums, int target){ if(nums.size() == 0) return -1; int left = 0, right = nums.size() - 1; while(left <= right){ // Prevent (left + right) overflow int mid = left + (right - left) / 2; if(nums[mid] == targe…

模板 #3: int binarySearch(vector<int>& nums, int target){ if (nums.size() == 0) return -1; int left = 0, right = nums.size() - 1; while (left + 1 < right){ // Prevent (left + right) overflow int mid = left + (right - left) / 2; if (nums[mid] ==…

目录 33/81搜索旋转排序数组 34在排序数组中查找元素的第一个和最后一个位置 35搜索插入位置 74搜索二维矩阵 300最长上升子序列,354俄罗斯套娃信封问题 33/81搜索旋转排序数组 假设按照升序排序的数组在预先未知的某个点上进行了旋转. ( 例如,数组 [0,1,2,4,5,6,7] 可能变为 [4,5,6,7,0,1,2] ). 思路: 设置左右指针开始进入二分循环 判断中间的数是否为target,否则通过比较nums[mid] < nums[right]确定是右边有序还是左边有序…

基础题之一,是混迹于各种难题的基础,有时会在小公司的大题见到,但更多的是见于选择题... 题意:在一个有序数列中,要插入数target,找出插入的位置. 楼主在这里更新了<二分查找综述>第一题的解法,比较类似,当然是今天临时写的. 知道了这题就完成了leetcode 4的第二重二分的写法了吧,楼主懒... class Solution { public: int searchInsert(vector<int>& nums, int target) { , r = nums…

一. 题目 1. Two Sum II Given an array of integers that is already sorted in ascending order, find two numbers such that they add up to a specific target number. The function twoSum should return indices of the two numbers such that they add up to the ta…

一. 题目 1. Two SumTotal Accepted: 241484 Total Submissions: 1005339 Difficulty: Easy Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would have exactly one solutio…

很多其它请关注我的HEXO博客:http://jasonding1354.github.io/ 简书主页:http://www.jianshu.com/users/2bd9b48f6ea8/latest_articles 二分查找 二分查找算法是一种在有序数组中查找某一特定元素的搜索算法.搜素过程从数组的中间元素開始,假设中间元素正好是要查找的元素,则搜索过程结束:假设某一特定元素大于或者小于中间元素,则在数组大于或小于中间元素的那一半中查找,并且跟開始一样从中间元素開始比較.假设在某一步骤数组…

二分查找 1.二分查找的时间复杂度分析: 二分查找每次排除掉一半不合适的值,所以对于n个元素的情况来说: 一次二分剩下:n/2 两次:n/4 m次:n/(2^m) 最坏情况是排除到最后一个值之后得到结果,所以:n/(2^m) = 1 2^m = n 所以时间复杂度为:log2(n) 2.二分查找的实现方法: (1)递归 int RecursiveBinSearch(int arr[], int bottom, int top, int key) { if (bottom <= top) { in…

A peak element is an element that is greater than its neighbors. Given an input array nums, where nums[i] ≠ nums[i+1], find a peak element and return its index. The array may contain multiple peaks, in that case return the index to any one of the pea…

Given an array of integers nums sorted in ascending order, find the starting and ending position of a given target value. Your algorithm's runtime complexity must be in the order of O(log n). If the target is not found in the array, return [-1, -1].…

二分查找算法尽管简单,但面试中也比較常见.经经常使用来在有序的数列查找某个特定的位置.在LeetCode用到此算法的主要题目有: Search Insert Position Search for a Range Sqrt(x) Search a 2D Matrix Search in Rotated Sorted Array Search in Rotated Sorted Array II 这类题目基本能够分为例如以下四种题型: 1. Search Insert Position和Searc…

Leetcode之二分法专题-704. 二分查找(Binary Search) 给定一个 n 个元素有序的(升序)整型数组 nums 和一个目标值 target  ,写一个函数搜索 nums 中的 target,如果目标值存在返回下标,否则返回 -1. 示例 1: 输入: nums = [-1,0,3,5,9,12], target = 9 输出: 4 解释: 9 出现在 nums 中并且下标为 4 示例 2: 输入: nums = [-1,0,3,5,9,12], target = 2 输出:…

本文介绍LeetCode上有关二分查找和贪心法的算法题,推荐刷题总数为16道.具体考点归纳如下: 一.二分查找 1.数学问题 题号:29. 两数相除,难度中等 题号:668. 乘法表中第k小的数,难度困难 题号:793. 阶乘函数后K个零,难度困难 2.实际场景问题 题号:174. 地下城游戏,难度困难 题号:911. 在线选举,难度中等 3.数组问题 题号:300. 最长上升子序列,难度中等 题号:363. 矩形区域不超过 K 的最大数值和,难度困难 4.特殊定义问题 题号:352. 将数据流…