String (1)--detect capital

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

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

1. All letters in this word is capitals, like "USA".
2. All letters in this word is not capitals, like "Leetcode".
3. Only the first letter of this word was capital if it had more than one letter, like "Google".

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

Example 1:

Input: "USA" output:true

Example 2:

Input: "FlaG" Output:false

Note:the input is a non-empty word consisting of uppercase and lowercase Latin letters.

A very simple problem, slag as I can only be violent solution:

1.brutal force/command-type programming

1  Public classSolution {2      Public BooleanDetectcapitaluse (String word) {3         Char[] Value =Word.tochararray ();4         if(value.length = = 1 | | word = =NULL) {5             return true;6         }7         BooleanSECISUC =false;8         if(Character.islowercase (value[0])) {9              for(intI=1; i<value.length; i++) {Ten                 if(Character.isuppercase (Value[i])) { One                     return false; A                 } -             } -}Else { theSECISUC = Character.isuppercase (value[1])?true:false; -             if(SECISUC) { -                  for(inti=2; i<value.length; i++) { -                     if(Character.islowercase (Value[i])) { +                         return false; -                     } +                 } A}Else { at                  for(inti=2; i<value.length; i++) { -                     if(Character.isuppercase (Value[i])) { -                         return false; -                     } -                 } -             } in         } -         return true; to     } +}

2. Brute Force solution upgrade version

1 public class solution {2 publicly     Boolean detectcapitaluse (String word) {3         int cnt = 0; 4 for         (char C:word.tochararray ()) if (' Z '-C >= 0) cnt++; 5         return ((cnt==0 | | cnt==word.length ()) | | (cnt==1 && ' Z '-word.charat (0) >=0 }7}    

3. Declarative programming

1  Public BooleanDetectcapitaluse (String word) {2         if(Word.length () < 2)return true;3         if(Word.touppercase (). Equals (word))return true;4         if(Word.substring (1). toLowerCase (). Equals (word.substring (1)))return true;5         return false;6}

4.RegEx

1  Public Boolean Detectcapitaluse (String word) {2     return word.matches ("[a-z]+|[ a-z]+| [A-z] [a-z]+ "); 3 }

String (1)--detect capital