66. Plus One@python

Given a non-empty array of digits representing a non-negative integer, plus 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 contain 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.

原题地址: Plus One

代码: 

class Solution(object):
    def plusOne(self, digits):
        """
        :type digits: List[int]
        :rtype: List[int]
        """
        n = len(digits)
        digits[n-1] += 1
        for i in range(n-1, 0, -1):
            digits[i-1] += digits[i] / 10
            digits[i] = digits[i] % 10
        if digits[0] == 10:
            digits[0] = 0
            digits.insert(0, 1)
        return digits

时间复杂度: O(n)

空间复杂度: O(1)