0989. Add to Array-Form of Integer.js

// 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 (BigInt(A.join("")) + BigInt(K) + "").split("").map(Number);
}
// Runtime: 168 ms, faster than 30.75% of JavaScript online submissions for Add to Array-Form of Integer.
// Memory Usage: 40 MB, less than 90.00% of JavaScript online submissions for Add to Array-Form of Integer.
// console.log(addToArrayForm([1,2,6,3,0,7,1,7,1,9,7,5,6,6,4,4,0,0,6,3],516))