The Plus One problem solved with Python

The challenge

Given a non-empty array of digits representing a non-negative integer, increment one to the integer.

The digits are stored such that the most significant digit is at the head of the list, and each element in the array contains a single digit.

You may assume the integer does not contain any leading zero, except the number 0 itself.

Example 1:

Input: [1,2,3]
Output: [1,2,4]
Explanation: The array represents the integer 123.

Example 2:

Input: [4,3,2,1]
Output: [4,3,2,2]
Explanation: The array represents the integer 4321.

The solution in Python

def plusOne(self, digits: List[int]) -> List[int]:
    # check that digits exists and is bigger than 0
    if len(digits)==0:
        # fail safe
        return digits
        # increment the number to a single integer
        number = int(''.join([str(k) for k in digits]))+1
        # return back a list representation
        return [int(k) for k in str(number)]
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Nageshwar Burman
Nageshwar Burman
23 days ago

Fails for numbers with leading zeros. E.g., 0906