Create 989. Add to Array-Form of Integer

Author: haibarawu

989. Add to Array-Form of Integer

@@ -0,0 +1,50 @@
+/*
+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
+*/
+
+
+class Solution {
+    public List<Integer> addToArrayForm(int[] A, int K) {
+        List<Integer> result = new ArrayList<>();
+        int digit;
+        int X = 0;
+
+        for (int i = 0; i < A.length; i++) {
+            digit = A[i];
+            X = X * 10 + digit;
+        }
+        
+        X = X + K;
+        
+        do {
+            result.add(0, X % 10);
+            X /= 10;
+        } while  (X > 0);
+        
+        return result;
+    }
+}