题解 | #句子逆序#倒着遍历（空格）（非空格）（截取加空格）

public class Main{
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        String s=sc.nextLine();
        StringBuilder sb=new StringBuilder();
        int n=s.length();
        int j=n-1;
        int i=n-1;
        while(j>=0){
            while(j>=0 && s.charAt(j)!=' '){
                j--;
            }
            sb.append(s.substring(j+1,i+1)+" ");
            while(j>=0 && s.charAt(j)==' '){
                j--;
            }
            i=j;
        }
        sb.deleteCharAt(sb.length()-1);
        System.out.println(sb.toString());
    }
}