其实一开始想错了,把这个问题想难了,导致没有思路,现在好了很多. 题目: Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero. For example, given array S = [-1, 0, 1, 2, -1, -4], A sol…

我现在在做一个叫<leetbook>的免费开源书项目,力求提供最易懂的中文思路,目前把解题思路都同步更新到gitbook上了,需要的同学可以去看看 书的地址:https://hk029.gitbooks.io/leetbook/ ` 018. 4Sum 问题 Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all uniqu…

这个问题是我目前的知识回答,不来,只有良好的网上搜索解决方案,发现 K Sum 它是一类问题,但是,互联网是没有更简洁的代码,我想对于谁刚开始学习的人.您可能仍然想看看这个问题该怎么解决,然后看看他们的利益扩展它. [称号] Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which give…

3Sum Closest Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each input would have exactly one solution. For example, given arr…

Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each input would have exactly one solution. For example, given array S = {-1 2…

转自  http://tech-wonderland.net/blog/summary-of-ksum-problems.html 前言: 做过leetcode的人都知道, 里面有2sum, 3sum(closest), 4sum等问题, 这些也是面试里面经典的问题, 考察是否能够合理利用排序这个性质, 一步一步得到高效的算法. 经过总结, 本人觉得这些问题都可以使用一个通用的K sum求和问题加以概括消化, 这里我们先直接给出K Sum的问题描述和算法(递归解法), 然后将这个一般性的方法套用…

3Sum Smaller Given an array of n integers nums and a target, find the number of index triplets i, j, k with 0 <= i < j < k < n that satisfy the condition nums[i] + nums[j] + nums[k] < target. For example, given nums = [-2, 0, 1, 3], and tar…

题目意思:给一个数组,给一个target,找三个数的和,这个和要与target距离最近,输出这个和 思路:这个题比3sum要稍微简单一点,如果需要优化,也可以去重,不过因为结果唯一,我没有去重. min abs(flag=num[i]+num[j]+num[k]-target),判断条件稍微调整,就是flag>0,则k-- flag<0,则j++,flag=0,则返回target class Solution { public: int threeSumClosest(vector<in…

探讨一下leetcode上的3Sum: Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero. Note: The solution set must not contain duplicate triplets. For example, g…

1. Two Sum 题目链接 题目要求: Given an array of integers, 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 target, where index1 must be less than ind…