View Code of Problem 50

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;


public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        StringBuilder stringBuilder = new StringBuilder(scanner.nextLine());
        int p = 0, q = 0;
        List<int[]> list = new ArrayList<>();

        for (int i = 0; i < stringBuilder.length(); i++) {
            if (stringBuilder.charAt(i) >= '0' && stringBuilder.charAt(i) <= '9') {
                if (p != q) {
                    int a[]=new int[2];
                    a[0] = p;
                    a[1] = q;
                    list.add(a);
                }
                q++;
                p=q;
            }else{
                q++;
            }
        }
        int a[]=new int[2];
        if (p!=q){
            a[0] = p;
            a[1] = q;
            list.add(a);
        }
        for (int i = list.size()-1; i >=0 ; i--) {
            a = list.get(i);
            stringBuilder.replace(a[0], a[1], "*");

        }
        System.out.println(stringBuilder);
    }
}