Reverse the ordering of words in a string

Question

I have this string s1 = \"My name is X Y Z\" and I want to reverse the order of the words so that s1 = \"Z Y X is name My\".

I can do it u

Answer 1

My version of using stack:

public class Solution {
    public String reverseWords(String s) {
        StringBuilder sb = new StringBuilder();
        String ns= s.trim();
        Stack reverse = new Stack();
        boolean hadspace=false;

        //first pass
        for (int i=0; i< ns.length();i++){
            char c = ns.charAt(i);
            if (c==' '){
                if (!hadspace){
                    reverse.push(c);
                    hadspace=true;
                }
            }else{
                hadspace=false;
                reverse.push(c);
            }
        }
        Stack t = new Stack();
        while (!reverse.empty()){
            char temp =reverse.pop();
            if(temp==' '){
                //get the stack content out append to StringBuilder
                while (!t.empty()){
                    char c =t.pop();
                    sb.append(c);
                }
                sb.append(' ');
            }else{
                //push to stack
                t.push(temp);
            }
        }
        while (!t.empty()){
            char c =t.pop();
            sb.append(c);
        }
        return sb.toString();
    }
}