Description
https://leetcode.com/problems/add-to-array-form-of-integer/
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
Example 4:
Input: num = [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
Constraints:
1 <= num.length <= 104
0 <= num[i] <= 9
num
does not contain any leading zeros except for the zero itself.1 <= k <= 104
Explanation
Convert the list to integer and plus it with k to get a sum. Then append all the digits of the sum to get a list.
Python Solution
class Solution:
def addToArrayForm(self, num: List[int], k: int) -> List[int]:
num_integer = 0
for n in num:
num_integer = num_integer * 10 + n
sum_num = num_integer + k
if sum_num == 0:
return [0]
results = []
while sum_num > 0:
results.append(sum_num % 10)
sum_num = sum_num // 10
return results[::-1]
- Time Complexity: O(N).
- Space Complexity: O(N).