A zero-indexed array A consisting of N different integers is given. The array contains all integers in the range [0, N - 1]. Sets S[K] for 0 <= K < N are defined as follows: S[K] = { A[K], A[A[K]], A[A[A[K]]], ... }. Sets S[K] are finite for each K…

Given an array of 2n integers, your task is to group these integers into n pairs of integer, say (a1, b1), (a2, b2), ..., (an, bn) which makes sum of min(ai, bi) for all i from 1 to n as large as possible. Example 1: Input: [1,4,3,2] Output: 4 Explan…

做leetcode题目的第二天,我是按照分类来做的,做的第一类是Array类,碰见的第二道题目,也就是今天做的这个,题目难度为hard.题目不难理解,但是要求到了时间复杂度,就需要好好考虑使用一下算法了.刚开始没啥思路,就用暴力的方法,用双层循环遍历的一下两个已经排好序的数组 ,在中间位置停止找道中位数.这样时间复杂度是肯定不能满足题目要求的,但是程序测试还是过了. 苦于自己没有思路,又不甘心就这样水过一道题,还是搜了一下博客,膜拜了一下大神.最好的方法是将中位数  -- 两个数组数据排好序之后…

Description Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array. Note: The number of elements initialized in nums1 and nums2 are m and n respectively. You may assume that nums1 has enough space (size that is gr…

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: Elements in a triplet (a,b,c) must be in non-descending order. (ie, a ≤ b ≤ c) The…

Array *532. K-diff Pairs in an Array 方案一:暴力搜索, N平方的时间复杂度,空间复杂度N 数组长度为10000,使用O(N平方)的解法担心TLE,不建议使用,尽管最终验证还是可以过. 方案二:哈希 时间复杂度N 空间复杂度N *1.two sum 思路: 使用hash, 顺序遍历数组,并记录每一个出现过的元素值和其下标,当遍历到当前元素时,查找target-当前元素值 是否出现在map中,存在则返回结果 *16. 3Sum Closest 思路一:暴力 fo…

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…

  思考的方向不对,即使用了多于别人几倍的时间,也不一定能够达到终点. 我的错误的想法(可以跳过):在leetcode上面做的第四道题,走路一个很大的弯路,收到之前做过的 Container With Most Water 的思路的影响,自己也想到了可以使用两个指针从左右遍历数组, 然而自己在这里走偏了,上来的第一个想法就是可以将整个解集合分为四种情况:全零,一正一负一零,两正一负,两负一正.这样整个程序就大致分为了四块,出现这种想法是由于我在第一层循环上面使用了两个指针向中间遍历,为内循环里面…

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. Example: Given nums = [2, 7, 11, 15]…

Description Given a binary array, find the maximum number of consecutive 1s in this array. Example 1: Input: [,,,,,] Output: Explanation: The first two digits or the last three digits are consecutive 1s. The maximum number of consecutive 1s . Note: T…