989. Add to Array-Form of Integer

Easy
The array-form of an integer num is an array representing its digits in left to right order.
  • For example, for num = 1321, the array form is [1,3,2,1].
Given num, the array-form of an integer, and an integer k, return the array-form of the integer num + k.
Example 1:
Input: num = [1,2,0,0], k = 34
Output: [1,2,3,4]
Explanation: 1200 + 34 = 1234
Example 2:
Input: num = [2,7,4], k = 181
Output: [4,5,5]
Explanation: 274 + 181 = 455
Example 3:
Input: num = [2,1,5], k = 806
Output: [1,0,2,1]
Explanation: 215 + 806 = 1021
Constraints:
  • 1 <= num.length <= 10^4
  • 0 <= num[i] <= 9
  • num does not contain any leading zeros except for the zero itself.
  • 1 <= k <= 10^4

解題

func addToArrayForm(num []int, k int) []int {
carry := k
for i:=len(num)-1; i>=0; i-- {
num[i] += carry
carry = num[i]/10
num[i] = num[i]%10
}
​
if carry != 0 {
for carry > 0 {
remainder := carry % 10
carry /= 10
num = append([]int{remainder}, num...)
}
}
​
return num
}