[leetcode]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].

var twoSum = function(nums, target) {
    var hash = {};
    for(var i = 0, n = nums.length; i< n; i++){
        var el = nums[i];
        if(el in hash){
            return [~~ hash[el], i]
          
        }
        hash[target-el] = i; 
    }
    return []
};