520. Detect Capital.md

520. Detect Capital

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leetcode Daily Challenge on August 1st, 2020.

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Difficulty : Easy

Related Topics : String

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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.

Example 1:

Input: "USA"
Output: True

Example 2:

Input: "FlaG"
Output: False

Note:

• The input will be a non-empty word consisting of uppercase and lowercase latin letters.

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Solution

• mine
  • Java
    • Runtime: 1 ms, faster than 99.86%, Memory Usage: 39.2 MB, less than 10.00% of Java online submissions

      // O(N)time
      // O(N)space
      public boolean detectCapitalUse(String word) {
          char[] arr = word.toCharArray();
          int count = 0;
          for(char c : arr){
              if(c <= 'Z'){
                  count++;
              }
          }
          if(count == arr.length || count == 0) return true;
      
          if(count == 1 && arr[0] <= 'Z') return true;
      
          return false;
      }
      

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• the most votes
  • Runtime: 2 ms, faster than 51.16%, Memory Usage: 39.5 MB, less than 5.71% of Java online submissions

    // O(N)time
    // O(N)space
    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)>=0));
    }
    

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