Given a non-negative number represented as an array of digits, plus one to the number.
The digits are stored such that the most significant digit is at the head of the list.
开始没有看明白题目到底啥意思,后来才发现是给定一个非负的整型数组,用来表示一个数字。最高位用数组里第一个数字表示。
Solution: 简单数学,加法进位,注意处理首位数字。
Running Time: O(n)
class Solution:
# @param digits, a list of integer digits
# @return a list of integer digits
def plusOne(self, digits):
for i in range(len(digits)-1, -1, -1):
if digits[i] != 9:
digits[i] += 1
break
else:
digits[i] = 0
if digits[0] == 0:
digits.insert(0, 1)
return digits