cansumnaive.js

// t/f
// use number from numbers as many times as needed to construct targetSum
const canSum = (targetSum, numbers) => {
  if (targetSum === 0) return true;
  for(let i = 0; i < numbers.length; i += 1) {
    const currentNum = numbers[i];
    const after = targetSum - currentNum;
    if (after < 0) continue;
    if(canSum(after, numbers)) return true;
  }
  return false;
};
console.log(canSum(7, [3, 4, 5, 7]));
console.log(canSum(7, [2, 4]));
// canSum(7, [3, 4, 5, 7]) -> true, as 3 + 4 = 7 or 7 = 7
// canSum(7, [2, 4]) -> false