package com.LeetCode; /** * 算法:二分搜索法查找一个值,并返回索引值 * https://leetcode.com/problems/search-insert-position/ * */public class BinSearch { public static void main(String[] args) {        int[] a = {1,3,5,6};        int[] b = {1,5,8, 13, 19};        int[]…

二分查找法作为一种常见的查找方法,将原本是线性时间提升到了对数时间范围,大大缩短了搜索时间,具有很大的应用场景,而在LeetCode中,要运用二分搜索法来解的题目也有很多,但是实际上二分查找法的查找目标有很多种,而且在细节写法也有一些变化.之前有网友留言希望博主能针对二分查找法的具体写法做个总结,博主由于之前一直很忙,一直拖着没写,为了树立博主言出必行的正面形象,不能再无限制的拖下去了,那么今天就来做个了断吧,总结写起来~ (以下内容均为博主自己的总结,并不权威,权当参考,欢迎各位大神们留言讨论…

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…

719. 找出第 k 小的距离对 给定一个整数数组,返回所有数对之间的第 k 个最小距离.一对 (A, B) 的距离被定义为 A 和 B 之间的绝对差值. 示例 1: 输入: nums = [1,3,1] k = 1 输出:0 解释: 所有数对如下: (1,3) -> 2 (1,1) -> 0 (3,1) -> 2 因此第 1 个最小距离的数对是 (1,1),它们之间的距离为 0. 提示: 2 <= len(nums) <= 10000. 0 <= nums[i] &l…

二分搜索法: 也称折半搜索,是一种在有序数组中查找特定元素的搜索算法. 实现步骤: 1. 首先从数组中间开始查找对比,若相等则找到,直接返回中间元素的索引. 2. 若查找值小于中间值,则在小于中间值的那一部分执行步骤1的操作. 3. 若查找值大于中间值,则在大于中间值的那一部分执行步骤1的操作. 4. 否则,返回结果为查不到,返回-1. 方法一: function binary_search1(arr, key) { var low = 0; var high = arr.length - 1;…

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;…

二分算法通常用于有序序列中查找元素: 有序序列中是否存在满足某条件的元素: 有序序列中第一个满足某条件的元素的位置: 有序序列中最后一个满足某条件的元素的位置. 思路很简单,细节是魔鬼. 一.有序序列中是否存在满足某条件的元素 首先,二分查找的框架: def binarySearch(nums, target): l = 0 #low h = ... #high ​ while l...h: m = (l + (h - l) / 2) #middle,防止h+l溢出 if nums[m] ==…

二分查找算法java实现 今天看了一下JDK里面的二分法是实现,觉得有点小问题.二分法的实现有多种今天就给大家分享两种.一种是递归方式的,一种是非递归方式的.先来看看一些基础的东西. 1.算法概念. 二分查找算法也称为折半搜索.二分搜索,是一种在有序数组中查找某一特定元素的搜索算法.请注意这种算法是建立在有序数组基础上的. 2.算法思想. ①搜素过程从数组的中间元素开始,如果中间元素正好是要查找的元素,则搜素过程结束: ②如果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…

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…

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…

题目 中位数是有序序列最中间的那个数.如果序列的大小是偶数,则没有最中间的数:此时中位数是最中间的两个数的平均数. 例如: [2,3,4],中位数是 3 [2,3],中位数是 (2 + 3) / 2 = 2.5 给出一个数组 nums,有一个大小为 k 的窗口从最左端滑动到最右端.窗口中有 k 个数,每次窗口移动 1 位.你的任务是找出每次窗口移动后得到的新窗口中元素的中位数,并输出由它们组成的数组. 例如: 给出 nums = [1,3,-1,-3,5,3,6,7],以及 k = 3. 窗口位…

二分 二分模板 两个模板:1.最大值最小模板一,2.最小值最大用模板二 单调性.两段性的性质 版本1:二分绿色端点是答案,最大值最小 int bsearch_1(int l, int r){ while (l < r){ int mid = l + r >> 1; //下取整 if (check(mid)) r = mid; else l = mid + 1; } return l; } 版本2:二分红色端点是答案,最小值最大 int bsearch_2(int l, int r){ w…

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] ==…

(1)4. 寻找两个有序数组的中位数(中) https://leetcode-cn.com/problems/median-of-two-sorted-arrays/ 给定两个大小为 m 和 n 的有序数组 nums1 和 nums2. 请你找出这两个有序数组的中位数,并且要求算法的时间复杂度为 O(log(m + n)). 你可以假设 nums1 和 nums2 不会同时为空. 示例 1: nums1 = [1, 3]nums2 = [2] 则中位数是 2.0示例 2: nums1 = [1,…

You have a total of n coins that you want to form in a staircase shape, where every k-th row must have exactly k coins. Given n, find the total number of full staircase rows that can be formed. n is a non-negative integer and fits within the range of…

Given an array which consists of non-negative integers and an integer m, you can split the array into m non-empty continuous subarrays. Write an algorithm to minimize the largest sum among these m subarrays. Note:Given m satisfies the following const…

Given a n x n matrix where each of the rows and columns are sorted in ascending order, find the kth smallest element in the matrix. Note that it is the kth smallest element in the sorted order, not the kth distinct element. Example: matrix = [ [ 1, 5…

We are playing the Guess Game. The game is as follows: I pick a number from 1 to n. You have to guess which number I picked. Every time you guess wrong, I'll tell you whether the number is higher or lower. You call a pre-defined API guess(int num) wh…

Given a non-empty 2D matrix matrix and an integer k, find the max sum of a rectangle in the matrix such that its sum is no larger than k. Example: Given matrix = [ [1, 0, 1], [0, -2, 3] ] k = 2 The answer is 2. Because the sum of rectangle [[0, 1], […

You are given an integer array nums and you have to return a new counts array. The counts array has the property where counts[i] is the number of smaller elements to the right of nums[i]. Example: Given nums = [5, 2, 6, 1] To the right of 5 there are…

An image is represented by a binary matrix with 0 as a white pixel and 1 as a black pixel. The black pixels are connected, i.e., there is only one black region. Pixels are connected horizontally and vertically. Given the location (x, y) of one of the…

Given an array nums containing n + 1 integers where each integer is between 1 and n (inclusive), prove that at least one duplicate element must exist. Assume that there is only one duplicate number, find the duplicate one. Note: You must not modify t…

You are a product manager and currently leading a team to develop a new product. Unfortunately, the latest version of your product fails the quality check. Since each version is developed based on the previous version, all the versions after a bad ve…

Follow up for H-Index: What if the citations array is sorted in ascending order? Could you optimize your algorithm? Hint: Expected runtime complexity is in O(log n) and the input is sorted. 这题是之前那道H-Index 求H指数的拓展,输入数组是有序的,让我们在O(log n)的时间内完成计算,看到这个时间复…