For a non-negative integer X, the array-form of X is an array of its digits in left to right

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:

Note:

1 <= A.length <= 10000 0 <= A[i] <= 9 0 <= K <= 10000 If A.length > 1, then A[0] != 0

Solution: O(N) use BigInteger to add long numbers