Algorithms in Javascript: 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.

leetcode-1-sum-of-two-indices.js

const twoSum = (a, target) => {  
  let len = a.length;
  if(a.length === 2) return [0, 1];
  for(let i=0; i<len; i++) {
    for (let j = i + 1; j < len; j++) {
      if(a[j] === target - a[i]) {
        return [i,j];
      }
    }
  }  
}

console.log(twoSum([1,2,3,4,5,6,7], 13));
console.log(twoSum([3,2,4], 6));
console.log(twoSum([3,3], 6));
console.log(twoSum([3,2,3], 6))