1.two-sum.0.js

/*
 * @lc app=leetcode id=1 lang=javascript
 *
 * [1] Two Sum
 *
 * https://leetcode.com/problems/two-sum/description/
 *
 * algorithms
 * Easy (42.90%)
 * Total Accepted:    1.6M
 * Total Submissions: 3.8M
 * Testcase Example:  '[2,7,11,15]\n9'
 *
 * 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], target = 9,
 * 
 * Because nums[0] + nums[1] = 2 + 7 = 9,
 * return [0, 1].
 * 
 * 
 * 
 * 
 */
/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
const twoSum = (nums, target) => {
    let index2 = null
    const index = nums.findIndex((num, i) => {
      index2 = nums.slice(i + 1).findIndex(num2 => num2 === target - num)
      return ~index2
    })
    return [index, index + index2 + 1]
  }