Reverse Words in a String

151. Reverse Words in a String

Given an input string s, reverse the order of the words.
A word is defined as a sequence of non-space characters. The words in s will be separated by at least one space.
Return a string of the words in reverse order concatenated by a single space.
Note that s may contain leading or trailing spaces or multiple spaces between two words.
The returned string should only have a single space separating the words. Do not include any extra spaces.

Example 1:
Input: s = "the sky is blue"
Output: "blue is sky the"

Example 2:
Input: s = "  hello world  "
Output: "world hello"
Explanation: Your reversed string should not contain leading or trailing spaces.

Example 3:
Input: s = "a good   example"
Output: "example good a"
Explanation: You need to reduce multiple spaces between two words to a single space in the reversed string.

class Solution {
    public String reverseWords(String s) {
       String[]str=s.trim().split("\\s+");
       String a="";
       for(int i=str.length-1;i>0;i--)
       {
         a=a+str[i]+" ";
        }
        return a+str[0]; 
    }
}