66. Plus One

https://leetcode.com/problems/plus-one/description/

You are given a large integer represented as an integer array digits, where each digits[i] is the ith digit of the integer. The digits are ordered from most significant to least significant in left-to-right order. The large integer does not contain any leading 0's.

Increment the large integer by one and return the resulting array of digits.

 

Example 1:

Input: digits = [1,2,3]
Output: [1,2,4]
Explanation: The array represents the integer 123.
Incrementing by one gives 123 + 1 = 124.
Thus, the result should be [1,2,4].
Example 2:

Input: digits = [4,3,2,1]
Output: [4,3,2,2]
Explanation: The array represents the integer 4321.
Incrementing by one gives 4321 + 1 = 4322.
Thus, the result should be [4,3,2,2].
Example 3:

Input: digits = [9]
Output: [1,0]
Explanation: The array represents the integer 9.
Incrementing by one gives 9 + 1 = 10.
Thus, the result should be [1,0].
 

Constraints:

1 <= digits.length <= 100
0 <= digits[i] <= 9
digits does not contain any leading 0's.

배열을 하나의 정수로 만들어준다.
그리고 1을 더하고, 이를 다시 배열로 만들어주면 끝.

class Solution:
    def plusOne(self, digits: List[int]) -> List[int]:
        a = 0
        ans = []
        for i in range(1, len(digits)+1):
            a += 10**(i-1)*digits[-i]
        a += 1
        b = str(a)
        for i in range(len(b)):
            ans.append(int(b[i]))
        return ans