LeetCode - Easy - 520. Detect Capital-蒲公英云

LeetCode - Easy - 520. Detect Capital

Topic

String

Description

https://leetcode.com/problems/detect-capital/

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, like "Google".

Given a string word, return true if the usage of capitals in it is right.

Example 1:

Input: word = "USA"
Output: true

Example 2:

Input: word = "FlaG"
Output: false

Constraints:

1 <= word.length <= 100
word consists of lowercase and uppercase English letters.

Analysis

方法一：字符统计

方法二：正则表达式

Submission

public class DetectCapital { 
    public boolean detectCapitalUse(String word) { 
        int capitalCount = 0, notCapitalCount = 0;
        boolean firstLetterCapital = Character.isUpperCase(word.charAt(0));
        for(int i = 0; i < word.length(); i++) { 
            if(Character.isUpperCase(word.charAt(i))) { 
                capitalCount++;
            }else { 
                notCapitalCount++;
            }
        }
        return firstLetterCapital && notCapitalCount == word.length() - 1 //
                || notCapitalCount == word.length()//
                || capitalCount == word.length(); 
    }
    public boolean detectCapitalUse2(String word) { 
        return word.matches("[A-Z]*|[A-Z]?[a-z]*");
    }
}

Test

public class DetectCapitalTest { 
    @Test
    public void test() { 
        DetectCapital obj = new DetectCapital();
        assertTrue(obj.detectCapitalUse("USA"));
        assertTrue(obj.detectCapitalUse("leetcode"));
        assertTrue(obj.detectCapitalUse("Google"));
        assertTrue(obj.detectCapitalUse("g"));
        assertFalse(obj.detectCapitalUse("FlaG"));
        assertTrue(obj.detectCapitalUse2("USA"));
        assertTrue(obj.detectCapitalUse2("leetcode"));
        assertTrue(obj.detectCapitalUse2("Google"));
        assertTrue(obj.detectCapitalUse2("g"));
        assertFalse(obj.detectCapitalUse2("FlaG"));
    }
}