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 unique quadruplets in the array which gives the sum of target. Note: Elements in a quadruplet (a,b,c,d) must be in non-descending order.…

18. 四数之和 给定一个包含 n 个整数的数组 nums 和一个目标值 target,判断 nums 中是否存在四个元素 a,b,c 和 d ,使得 a + b + c + d 的值与 target 相等?找出所有满足条件且不重复的四元组. 注意: 答案中不可以包含重复的四元组. 示例: 给定数组 nums = [1, 0, -1, 0, -2, 2],和 target = 0. 满足要求的四元组集合为: [ [-1, 0, 0, 1], [-2, -1, 1, 2], [-2, 0, 0,…

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 unique quadruplets in the array which gives the sum of target. Note: The solution set must not contain duplicate quadruplets. For exampl…

一.题目链接:https://leetcode.com/problems/4sum/ 二.题目大意: 给定一个数组A和一个目标值target,要求从数组A中找出4个数来使之构成一个4元祖,使得这四个数的和等于target,找出所有的四元组,当然这些四元组不能有重复的. 三.题解: 这道题实质就是3sum的变形,关于4sum问题,已经在https://www.cnblogs.com/wangkundentisy/p/9079622.html这里说过了,无外乎最外面两层循环,最里面的循环使用哈希表或…

题目链接 https://leetcode.com/problems/4sum/?tab=Description 找到数组中满足 a+b+c+d=0的所有组合,要求不重复. Basic idea is using subfunctions for 3sum and 2sum, and keeping throwing all impossible cases. O(n^3) time complexity, O(1) extra space complexity. 首先进行判断,由于是四个数相加…

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 unique quadruplets in the array which gives the sum of target. Note: The solution set must not contain duplicate quadruplets. For exampl…

链接 4Sum 难度 Medium 描述 Given an array nums of n integers and an integer target, are there elements a , b , c , and d in nums such that a + b + c + d = target? Find all unique quadruplets in the array which gives the sum of target. 给定一个n个整数的数组n,和一个整数tar…

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 unique quadruplets in the array which gives the sum of target. Note: The solution set must not contain duplicate quadruplets. For exampl…

问题描述: 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 unique quadruplets in the array which gives the sum of target. Note: Elements in a quadruplet (a,b,c,d) must be in non-descending…

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 unique quadruplets in the array which gives the sum of target. Note: Elements in a quadruplet (a,b,c,d) must be in non-descending order.…