AddToArrayFormOfInteger.js

// Source : https://leetcode.com/problems/add-to-array-form-of-integer/
// Author : Dean Shi
// Date   : 2019-03-14

/***************************************************************************************
 *
 * For a non-negative integer X, the array-form of X is an array of its digits in left
 * to right order.  For example, if X = 1231, then the array form is [1,2,3,1].
 *
 * Given the array-form A of a non-negative integer X, return the array-form of the
 * integer X+K.
 *
 * Example 1:
 *
 * Input: A = [1,2,0,0], K = 34
 * Output: [1,2,3,4]
 * Explanation: 1200 + 34 = 1234
 *
 * Example 2:
 *
 * Input: A = [2,7,4], K = 181
 * Output: [4,5,5]
 * Explanation: 274 + 181 = 455
 *
 * Example 3:
 *
 * Input: A = [2,1,5], K = 806
 * Output: [1,0,2,1]
 * Explanation: 215 + 806 = 1021
 *
 * Example 4:
 *
 * Input: A = [9,9,9,9,9,9,9,9,9,9], K = 1
 * Output: [1,0,0,0,0,0,0,0,0,0,0]
 * Explanation: 9999999999 + 1 = 10000000000
 *
 * Note：
 *
 * 1 <= A.length <= 10000
 * 0 <= A[i] <= 9
 * 0 <= K <= 10000
 * If A.length > 1, then A[0] != 0
 *
 ***************************************************************************************/

/**
 * @param {number[]} A
 * @param {number} K
 * @return {number[]}
 */
var addToArrayForm = function(A, K) {
    return Array.from((BigInt(A.join('')) + BigInt(K)).toString())
};