OlympiadCode/leetcode_py/66.py

"""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.
"""

from typing import List
class Solution:
    def plusOne(self, digits: List[int]) -> List[int]:
        n = len(digits)
        # Start from the rightmost digit
        for i in range(n - 1, -1, -1):
            # If the current digit is less than 9, just increment it by 1 and return
            if digits[i] < 9:
                digits[i] += 1
                return digits
            # Otherwise, set the current digit to 0 and continue with the next digit
            else:
                digits[i] = 0
        # If we reach here, it means all digits were 9, so we need to add a new leading 1
        digits.insert(0, 1)
        return digits