Problem013.js

/**
 * Work out the first ten digits of the sum of the following one-hundred 50-digit numbers.
 */

export function largeSum(bignum) {
 const nums = []
 for (let i = 0; i < bignum.length; i += 50) {
 nums.push(bignum.slice(i, i + 50))
 }

 let pos = nums[0].length
 let ret = ''
 let num = 0

 while (pos--) {
 for (let i = nums.length; i--; ) {
 num += +nums[i].charAt(pos)
 }
 ret = (num % 10) + ret
 num = (num / 10) | 0
 }

 if (num > 0) {
 ret = num + ret
 }
 return ret.slice(0, 10)
}