66. Plus One

LeetCode problem

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].

First accepted

class Solution:
    def plusOne(self, digits: List[int]) -> List[int]:
        i = len(digits) - 1
        
        while i >= 0 and digits[i] == 9:
            digits[i] = 0
            i -= 1
        
        if i < 0:
            return [1] + digits
        digits[i] = digits[i] + 1
        
        return digits