LeetCode 练习1

原创于 2018-04-29 23:43:36 发布 · 169 阅读

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本文介绍了如何使用Python实现整数加一的功能，并通过数组操作完成。此外，还提供了字符串反转的方法，这两种算法都是通过简单的迭代实现的。

66. Plus One

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.

class Solution:
    def plusOne(self, digits):
        """
        :type digits: List[int]
        :rtype: List[int]
        """
        for i in range(len(digits)-1, -1, -1):
            if digits[i] < 9:
                digits[i] += 1
                return digits
            else:
                digits[i] = 0
        digits.insert(0, 1)
        return digits

344. Reverse String

Write a function that takes a string as input and returns the string reversed.

class Solution:
    def reverseString(self, s):
        """
        :type s: str
        :rtype: str
        """
        return s[::-1]

520. Detect Capital

Given a word, you need to judge whether the usage of capitals in it is right or not.

We define the usage of capitals in a word to be right when one of the following cases holds:

All letters in this word are capitals, like "USA".
All letters in this word are not capitals, like "leetcode".
Only the first letter in this word is capital if it has more than one letter, like "Google".

Otherwise, we define that this word doesn't use capitals in a right way.

class Solution:
    def detectCapitalUse(self, word):
        """
        :type word: str
        :rtype: bool
        """
        if word.lower() == word or word.upper() == word or word== word.title(): 
            return True
        return False