520. Detect Capital

最新推荐文章于 2025-01-03 07:15:00 发布

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本文介绍了一种用于检查字符串中大小写使用是否正确的算法。该算法提供了三种不同的实现方式，包括全大写检查、首字母大写及其余小写检查等。这些方法可以帮助开发者快速验证单词的大小写格式是否符合规定。

题目描述：

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.

思路一：

*全大写

*首字母任意，从第二个起全小写

class Solution {
    public boolean detectCapitalUse(String word) {
        String upper = word.toUpperCase();
        if (upper.equals(word))
            return true;
        else
        {
            String lower = word.substring(1).toLowerCase();
            if (lower.equals(word.substring(1)))
                return true;
        }
        return false;
    }
}

思路二：

*全大写

*全小写

*首字母大写，其余小写

class Solution {
    public boolean detectCapitalUse(String word) {
        int cnt = 0;
        for (char c : word.toCharArray())
            if ('Z' - c >= 0)
                cnt++;
        return (cnt == 0 || cnt == word.length() || ((cnt == 1) && ('Z' >= word.charAt(0))));
    }
}

思路三：判断首字母

class Solution {
    public boolean detectCapitalUse(String word) {
        if (word.length() == 1)
            return true;
        return Character.isUpperCase(word.charAt(0)) ? (word.substring(1).equals(word.substring(1).toLowerCase()) || word.substring(1).equals(word.substring(1).toUpperCase())) : (word.equals(word.toLowerCase()));
    }
}