LeetCode 1. Two Sum （JavaScript）

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.

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[]}
 */
var twoSum = function(nums, target) {
    let map=new Map();
    for(let i=0;i<nums.length;i++){
        let index=map.get(target-nums[i]);
        if(index!=undefined){
            return [index,i];
        }
        map.set(nums[i],i);
    }
};