LeetCode - Easy - 520. Detect Capital

柔情只为你懂 2022-10-15 04:44 162阅读 0赞

## Topic ##

*  String

## Description ##

[https://leetcode.com/problems/detect-capital/][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"));
    		
    	}
    }

[https_leetcode.com_problems_detect-capital]: https://leetcode.com/problems/detect-capital/