C++ :

#include <iostream>
using namespace std;
int josephus(int n,int k,int m,int p){
	int r = 0;
	for(int i=n-p+1;i<=n;i++)
		r = (r+k-1)%i+1;
	return (r+m-k%n-1+n)%n+1;}
int main(){
	for(int n,k,m,p;cin>>n>>k>>m>>p && !(n+m+k+p == 0);)
		cout<<josephus(n,k,m,p)<<endl;
	return 0;}

Java :

import java.util.*;
public class Main {
		static ArrayList<Integer> list =null;
		private static Scanner in;
		
		public static void main(String[] args) {
			
			 in = new Scanner(System.in);
			 int n,k,m,p,a,c,count,temp=0,x=0;
			while(in.hasNext()){
				count=1;
				x=0;
				n=in.nextInt();
				k=in.nextInt();
				m=in.nextInt();
				p=in.nextInt();
				if(n==0&&k==0&&m==0&&p==0) break;
				list = new ArrayList<Integer>();
				creatList( n);
				if(m%n==0)
					m=n-1;
	            else
	                m=m%n-1;

				if(count==p){
					System.out.println(list.get(m));
					continue;
				}
				list.remove(m);
				
				while(list.size()!=1){
					if(list.size()-m>k){
						temp = list.get(m+k-1);
						list.remove(m+k-1);
						count++;
						m=m+k-1;
					}else if(list.size()-m<k){
						c=k-(list.size()-m);
						a=0;
						while(true){
							if(a+c<list.size()){
								temp = list.get(a+c-1);
								list.remove(a+c-1);
								count++;
								m=a+c-1;
								break;
							}
							else if(a+c>list.size()){
								c=c-(list.size()-a);
								a=0;
							}else{
								temp = list.get(a+c-1);
								list.remove(a+c-1);
								count++;
								m=0;
								break;
							}
								
						}
					}else {
						temp = list.get(list.size()-1);
						list.remove(list.size()-1);
						count++;
						m=0;
					}
					if(count==p){
						System.out.println(temp);
						x=1;
						break;
					}
				}
				if(list.size()==1&&x==0)
					System.out.println(list.get(0));
				
			}
		}
		public static void creatList(int n){
			for(int i=1;i<=n;i++){
				list.add(i);
			}
			
		}
}