Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

1. 两数之和 #1

Open
webVueBlog opened this issue Sep 8, 2022 · 0 comments
Open

1. 两数之和 #1

webVueBlog opened this issue Sep 8, 2022 · 0 comments

Comments

@webVueBlog
Copy link
Owner

webVueBlog commented Sep 8, 2022

1. 两数之和

Description

Difficulty: 简单

Related Topics: 数组, 哈希表

给定一个整数数组 nums 和一个整数目标值 target,请你在该数组中找出 和为目标值 target  的那 两个 整数,并返回它们的数组下标。

你可以假设每种输入只会对应一个答案。但是,数组中同一个元素在答案里不能重复出现。

你可以按任意顺序返回答案。

示例 1:

输入:nums = [2,7,11,15], target = 9
输出:[0,1]
解释:因为 nums[0] + nums[1] == 9 ,返回 [0, 1] 。

示例 2:

输入:nums = [3,2,4], target = 6
输出:[1,2]

示例 3:

输入:nums = [3,3], target = 6
输出:[0,1]

提示:

  • 2 <= nums.length <= 104
  • -109 <= nums[i] <= 109
  • -109 <= target <= 109
  • 只会存在一个有效答案

**进阶:**你可以想出一个时间复杂度小于 O(n2) 的算法吗?

Solution

Language: JavaScript

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = function(nums, target) {
    let map = new Map()
    for (let i = 0; i < nums.length; i++) {
        if (map.has(target - nums[i])) {
            return [map.get(target-nums[i]), i]
        }
        map.set(nums[i], i)
    }
    return [-1, -1]
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

No branches or pull requests

1 participant