[Swift Weekly Contest 123]LeetCode989. 数组形式的整数加法 | Add to Array-Form of Integer

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. 1 <= A.length <= 10000
2. 0 <= A[i] <= 9
3. 0 <= K <= 10000
4. If A.length > 1, then A[0] != 0

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对于非负整数 X 而言，X 的数组形式是每位数字按从左到右的顺序形成的数组。例如，如果 X = 1231，那么其数组形式为 [1,2,3,1]。

给定非负整数 X 的数组形式 A，返回整数 X+K 的数组形式。 

示例 1：

输入：A = [1,2,0,0], K = 34
输出：[1,2,3,4]
解释：1200 + 34 = 1234

解释 2：

输入：A = [2,7,4], K = 181
输出：[4,5,5]
解释：274 + 181 = 455

示例 3：

输入：A = [2,1,5], K = 806
输出：[1,0,2,1]
解释：215 + 806 = 1021

示例 4：

输入：A = [9,9,9,9,9,9,9,9,9,9], K = 1
输出：[1,0,0,0,0,0,0,0,0,0,0]
解释：9999999999 + 1 = 10000000000

提示：

1. 1 <= A.length <= 10000
2. 0 <= A[i] <= 9
3. 0 <= K <= 10000
4. 如果 A.length > 1，那么 A[0] != 0

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Runtime: 336 ms

Memory Usage: 13.8 MB

 1 class Solution {
 2     func addToArrayForm(_ A: [Int], _ K: Int) -> [Int] {
 3         var A = A
 4         var n:Int = A.count
 5         var c:Int = K
 6         for i in stride(from:A.count - 1,through:0,by:-1)
 7         {
 8             A[i] += c
 9             c = A[i] / 10
10             A[i] %= 10          
11         }
12         var ret:[Int] = [Int]()
13         while(c > 0)
14         {
15             ret.insert(c%10,at:0)
16             c /= 10
17         }
18         for v in A
19         {
20             ret.append(v)
21         }
22         return ret
23     }
24 }