15. 3Sum(中等)】的更多相关文章

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, given array S = [-1,…
LeetCode 15 3Sum [sort] <c++> 给出一个一维数组,找出其中所有和为零的三元组(元素集相同的视作同一个三元组)的集合. C++ 先自己写了一发,虽然过了,但跑了308 ms... 我的做法是先排序,扫一遍,处理出unorder_map<0-a[i],i>的hash表.再\(O(n^2)\)枚举前两个元素,查表直接知道第三个元素的位置,然后将三元组加入到答案集合中,通过枚举时添加的限制条件规避重复元素. 复杂度\(O(n^2)\),由于使用了hash表,常数…
题目: 1. Two Sum 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 solution, and you may not use the same element twice. Given nums = [2, 7, 1…
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…
传送门 15. 3Sum My Submissions Question Total Accepted: 108534 Total Submissions: 584814 Difficulty: Medium 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 su…
15 3sum Given an array nums of n integers, are there elements a, b, c in nums 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. Example: Given array…
一.题目说明 题目非常简洁15. 3Sum,读懂题目后,理解不难. 但 实话说,我们提交代码后,Time Limit Exceeded,最主要的是给了非常长的测试用例,我本地运行后87秒,确实时间非常长. 二.我的解答及问题 下面是我的解答代码,通过该例子可以学习如何写测试代码: #include<iostream> #include<vector> #include<unordered_map> #include<algorithm> using name…
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: Elements in a triplet (a,b,c) must be in non-descending order. (ie, a ≤ b ≤ c) The solut…
n数求和,固定n-2个数,最后两个数在连续区间内一左一右根据当前求和与目标值比较移动,如果sum<target,移动较小数,否则,移动较大数 重复数处理: 使i为左至右第一个不重复数:while(i != 0 && i<n-2 && a[i] == a[i-1]) i++; 使r为右至左第一个不重复数(原序最后一个):while(r>i && r+1<n && a[r] == a[r+1]) r--; 15. 3Sum…
参考资料: https://leetcode.com/problems/3sum/discuss/7402/Share-my-AC-C%2B%2B-solution-around-50ms-O(N*N)-with-explanation-and-comments https://www.cnblogs.com/grandyang/p/4481576.html class Solution { public: vector<vector<int>> threeSum(vector&l…