454. 4Sum II Add to List Description Submission Solutions Total Accepted: 8398 Total Submissions: 18801 Difficulty: Medium Contributors: Samuri Given four lists A, B, C, D of integer values, compute how many tuples (i, j, k, l) there are such that A[…

Given four lists A, B, C, D of integer values, compute how many tuples (i, j, k, l) there are such that A[i] + B[j] + C[k] + D[l] is zero. To make problem a bit easier, all A, B, C, D have same length of N where 0 ≤ N ≤ 500. All integers are in the r…

Given four lists A, B, C, D of integer values, compute how many tuples (i, j, k, l) there are such that A[i] + B[j] + C[k] + D[l] is zero. To make problem a bit easier, all A, B, C, D have same length of N where 0 ≤ N ≤ 500. All integers are in the r…

▶ 问题:给定一个数组 nums 及一个目标值 target,求数组中是否存在 n 项的和恰好等于目标值 ▶ 第 1题,n = 2,要求返回解 ● 代码,160 ms,穷举法,时间复杂度 O(n2),空间复杂度 O(1) class Solution { public: vector<int> twoSum(vector<int> nums, int target) { int i, j; ; i < nums.size()-; i++) { ; j < nums.si…

Given four lists A, B, C, D of integer values, compute how many tuples (i, j, k, l) there are such that A[i] + B[j] + C[k] + D[l] is zero. To make problem a bit easier, all A, B, C, D have same length of N where 0 ≤ N ≤ 500. All integers are in the r…

Given four lists A, B, C, D of integer values, compute how many tuples (i, j, k, l) there are such that A[i] + B[j] + C[k] + D[l] is zero. To make problem a bit easier, all A, B, C, D have same length of N where 0 ≤ N ≤ 500. All integers are in the r…

Given four lists A, B, C, D of integer values, compute how many tuples (i, j, k, l) there are such that A[i] + B[j] + C[k] + D[l] is zero. To make problem a bit easier, all A, B, C, D have same length of N where 0 ≤ N ≤ 500. All integers are in the r…

题目: Given four lists A, B, C, D of integer values, compute how many tuples (i, j, k, l) there are such that A[i] + B[j] + C[k] + D[l] is zero. To make problem a bit easier, all A, B, C, D have same length of N where 0 ≤ N ≤ 500. All integers are in t…

题目: Given four lists A, B, C, D of integer values, compute how many tuples (i, j, k, l) there are such that A[i] + B[j] + C[k] + D[l] is zero. To make problem a bit easier, all A, B, C, D have same length of N where 0 ≤ N ≤ 500. All integers are in t…

给定四个包含整数的数组列表 A , B , C , D ,计算有多少个元组 (i, j, k, l) ,使得 A[i] + B[j] + C[k] + D[l] = 0.为了使问题简单化,所有的 A, B, C, D 具有相同的长度 N,且 0 ≤ N ≤ 500 .所有整数的范围在 -228 到 228 - 1 之间,最终结果不会超过 231 - 1 .例如:输入:A = [ 1, 2]B = [-2,-1]C = [-1, 2]D = [ 0, 2]输出:2解释:两个元组如下:1. (0,…

要求 给出四个整型数组ABCD,寻找有多少 i j k l 的组合,使得A[i]+B[j]+C[k]+D[l]=0 ABCD元素个数均为N,0<=N<=500 示例 输入: A = [ 1, 2] B = [-2,-1] C = [-1, 2] D = [ 0, 2] 输出:2 1. (0, 0, 0, 1) -> A[0] + B[0] + C[0] + D[1] = 1 + (-2) + (-1) + 2 = 0 2. (1, 1, 0, 0) -> A[1] + B[1] +…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 字典 日期 题目地址:https://leetcode.com/problems/4sum-ii/description/ 题目描述 Given four lists A, B, C, D of integer values, compute how many tuples (i, j, k, l) there are such that A[i]…

Given four lists A, B, C, D of integer values, compute how many tuples (i, j, k, l) there are such that A[i] + B[j] + C[k] + D[l] is zero. To make problem a bit easier, all A, B, C, D have same length of N where 0 ≤ N ≤ 500. All integers are in the r…

Given four lists A, B, C, D of integer values, compute how many tuples (i, j, k, l) there are such that A[i] + B[j] + C[k] + D[l] is zero. To make problem a bit easier, all A, B, C, D have same length of N where 0 ≤ N ≤ 500. All integers are in the r…

Given four lists A, B, C, D of integer values, compute how many tuples (i, j, k, l)there are such that A[i] + B[j] + C[k] + D[l] is zero. To make problem a bit easier, all A, B, C, D have same length of N where 0 ≤ N ≤ 500. All integers are in the ra…

https://leetcode.com/submissions/detail/153740275/ class Solution { public: int fourSumCount(vector<int>& A, vector<int>& B, vector<int>& C, vector<int>& D) { unordered_map<int,int> CD_freq; for (auto i : C) f…

1.two sum 用hash来存储数值和对应的位置索引,通过target-当前值来获得需要的值,然后再hash中寻找 错误代码1: Input:[3,2,4]6Output:[0,0]Expected:[1,2] 同一个数字不能重复使用,但这个代码没排除这个问题 class Solution { public: vector<int> twoSum(vector<int>& nums, int target) { vector<int> result; uno…

作者: 负雪明烛 id: fuxuemingzhu 个人博客:http://fuxuemingzhu.cn/ 个人公众号:负雪明烛 本文关键词:four sum, 4sum, 四数之和,题解,leetcode, 力扣,Python, C++, Java 目录 题目描述 题目大意 解题方法 遍历 相似题目 参考资料 日期 题目地址:https://leetcode.com/problems/4sum/description/ 题目描述 Given an array nums of n intege…

终于将LeetCode的免费题刷完了,真是漫长的第一遍啊,估计很多题都忘的差不多了,这次开个题目汇总贴,并附上每道题目的解题连接,方便之后查阅吧~ 477 Total Hamming Distance 44.10% Meidum 475 Heaters  30.20% Easy 474 Ones and Zeroes  34.90% Meidum 473 Matchsticks to Square  31.80% Medium 472 Concatenated Words 29.20% Hard…

463. Island Perimeterhttps://leetcode.com/problems/island-perimeter/就是逐一遍历所有的cell,用分离的cell总的的边数减去重叠的边的数目即可.在查找重叠的边的数目的时候有一点小技巧,就是沿着其中两个方向就好,这种题目都有类似的规律,就是可以沿着上三角或者下三角形的方向来做.一刷一次ac,但是还没开始注意codestyle的问题,需要再刷一遍. class Solution { public: int islandPerime…

299. Bulls and Cows 思路:抽屉法,放进secrets,拿出guess,最终cows = cows - bulls public String getHint(String secret, String guess) { int bulls = 0; int cows = 0; int[] numbers = new int[10]; for(int i = 0; i < secret.length(); i++){ if(secret.charAt(i) == guess.c…

1. Two Sum https://leetcode.com/problems/two-sum/description/ 不使用额外空间需要n*n的复杂度 class Solution { public: vector<int> twoSum(vector<int>& nums, int target) { ;i<nums.size()-;i++){ ;j<nums.size();j++){ if(nums[i] + nums[j] == target){ v…

2018-05-03 刷了牛客网的题目:总结思路(总的思路跟数学一样就是化简和转化) 具体启发点: 1.对数据进行预处理排序的思想:比如8皇后问题 2.对一个数组元素进行比较的操作,如果复杂,可以试试倒过来,从最后一个元素往前面想. 3.动态规划,分治法. 4.超复杂的循环最好的方法是while 1:这种写法.(因为他最大程度保证了灵活性,比如leecode的283题) leecode习题: 主要是目前在学习 玩转算法面试 leetcode 这个课程,他把leecode的题目做分类,将例题,留习…

突然很想刷刷题,LeetCode是一个不错的选择,忽略了输入输出,更好的突出了算法,省去了不少时间. dalao们发现了任何错误,或是代码无法通过,或是有更好的解法,或是有任何疑问和建议的话,可以在对应的随笔下面评论区留言,我会及时处理,在此谢过了. 过程或许会很漫长,也很痛苦,慢慢来吧. 编号 题名 过题率 难度 1 Two Sum 0.376 Easy 2 Add Two Numbers 0.285 Medium 3 Longest Substring Without Repeating C…

454. 4Sum II 题意:给四个数组,每个数组内取一个数使得四个数和为0,问有多少种取法 思路:枚举为On4,考虑两个数组,On2枚举所有可能的和,将和的出现次数存入map中,On2枚举另两个数组,看是否加和为0 class Solution { public: int fourSumCount(vector<int>& A, vector<int>& B, vector<int>& C, vector<int>& D)…

今天看到这道题目:http://www.cnblogs.com/charlesblc/p/5930311.html 题目地址:https://leetcode.com/problems/split-array-largest-sum/ 很好,也很难.开拓了思路,用二分法来查找结果备选,然后直接划分原集合,来反过来是否是合理的解.是或者不是的话,继续向相应的方向进行二分.   # Title Editorial Acceptance Difficulty Frequency   . 454 4Su…

Hash Table基础 哈希表(Hash Table)是常用的数据结构,其运用哈希函数(hash function)实现映射,内部使用开放定址.拉链法等方式解决哈希冲突,使得读写时间复杂度平均为O(1). HashMap(std::unordered_map).HashSet(std::unordered_set)的原理与Hash Table一样,它们的用途广泛.用法灵活,接下来侧重于介绍它们的应用. 相关LeetCode题: 706. Design HashMap  题解  705. Des…

All LeetCode Questions List(Part of Answers, still updating) 题目汇总及部分答案(持续更新中) Leetcode problems classified by company 题目按公司分类(Last updated: October 2, 2017) .   Top Interview Questions # Title Difficulty Acceptance 1 Two Sum Medium 17.70% 2 Add Two N…

源代码地址:https://github.com/hopebo/hopelee 语言:C++ 301. Remove Invalid Parentheses Remove the minimum number of invalid parentheses in order to make the input string valid. Return all possible results. Note: The input string may contain letters other tha…

LeetCode Top Interview Questions https://leetcode.com/problemset/top-interview-questions/ # No. Title Acceptance Difficulty 1 1 Two Sum 38.80% Easy 2 2 Add Two Numbers 29.10% Medium 3 3 Longest Substring Without Repeating Characters 25.00% Medium 4 4…