UVa 133 - The Dole Queue

#include <cstdio>
#include <iostream>
#include <cstring>
using namespace std;
int n,k,m,num;
int a[25];
int find(int pos,int x,int m)
{
    while(m--)
    { 
        pos=(pos+x+n-1)%n+1;
        while(a[pos]) pos=(pos+x+n-1)%n+1;
        //cout<<pos<<endl;
    }
    return pos;
}
int main()
{
    while(~scanf("%d%d%d",&n,&k,&m)&&(n+k+m))
    {
        memset(a,0,sizeof(a));
        num=n;
        int p1=n,p2=1;
        while(num)
        {
            p1=find(p1,1,k);
            p2=find(p2,-1,m);
            printf("%3d",p1); num--;
            if(p1!=p2) { printf("%3d",p2); num--; }
            a[p1]=a[p2]=1;
            if(num) printf(",");
        }
        puts("");
    }
    return 0;
}