题目: 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 = [, , , ],…

题目在这里: https://leetcode.com/problems/two-sum/ [标签]Array; Hash Table [个人分析] 这个题目,我感觉也可以算是空间换时间的例子.如果是O(n^2)的那种思路,就是对于一个数字,去扫剩下的所有数字,看有没有能够加起来和为target的组合.但是如果加入一个哈希表,我们扫过的数字都可以记录下来. 我用的是 (target - number) 作为key, 用number在nums中的 index 作为 value, 遇到一个新的数字n…

索引 思路1:暴力搜索 思路2:聪明一点的搜索 思路3:利用HashMap巧解 问题描述:https://leetcode.com/problems/two-sum/ 思路1:暴力搜索 一个很自然的想法就是暴力搜索了.根据排列组合原理,列举Cn取2对数字,逐对进行判断,效率是O(n^2-1/2n),代码如下: var twoSum = function(nums, target) { for (let i = 0; i != nums.length; ++i) { for (let j = i…

1.题目要求 给定一个整数数组和一个目标值,找出数组中和为目标值的两个数. 你可以假设每个输入只对应一种答案,且同样的元素不能被重复利用. 示例: 2.解法一:暴力法(for*for,O(n*n)) 分析:因为题目假设“每个输入只对应一种答案,且相同的元素不能被重复利用”,这就降低了难度. 暴力法:使用两次for循环.第一个for循环依次遍历一次数组,每次执行过程中选取了一个数组元素nums[i], 再for循环遍历nums[i]后面的所有元素,假设取到的元素为nums[j](其中,i+1=<…

1 Two Sum Difficulty: Easy The Link: https://leetcode.com/problems/two-sum/description/ Description : Given an array of integers, return indices(索引) of the two numbers such that they add up to a specific target. You may assume that each input would h…

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 index2. Please note that…

题目: Find the contiguous subarray within an array (containing at least one number) which has the largest product. For example, given the array [2,3,-2,4], the contiguous subarray [2,3] has the largest product = 6. 题意: 题目中给出一个(至少包含一个元素)整形数组,求一个子数组(元素连续…

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. Example: Given nums = [2, 7, 11, 15], target = 9, Because nums[0] + nums[1] = 2…

Description 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. 题意 给定一个数组,和一个定值,找出数组元素的两…

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. Example: Given nums = [2, 7, 11, 15], target = 9, Because nums[0] + nums[1] = 2…