Reverse Words in a String

Given an input string, reverse the string word by word.

For example,
Given s = " the sky is blue ",
Return " blue is sky the ".

Clarification

• What constitutes a word?
  A sequence of non-space characters constitutes a word.
• Could the input string contain leading or trailing spaces?
  Yes. However, your reversed string should not contain leading or trailing spaces.
• How about multiple spaces between and words?
  Reduce them to a single space in the reversed string.

Idea: Using the split method of string to split, the regular expression of its segmentation is "".

1  Public classSolution {2     /**3      * @params:a String4      * @return: A string5      */6      Publicstring Reversewords (string s) {7         if(s = =NULL|| S.length () = = 0) {8             return"";9         }Tenstring[] Words = S.split (""); OneStringBuilder Builder =NewStringBuilder (); A          for(inti = words.length-1; I >= 0; i--) { -             if(Words[i]! = "") { -Builder.append (Words[i]). Append (""); the             } -         } -         returnBuilder.length () = = 0? "": builder.substring (0, Builder.length ()-1); -     } +}

Reverse Words in a String