SPOJ AMR10I Dividing Stones --DFS

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <set>
#define ll long long
using namespace std;
#define N 100007

int prime[22] = {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71};
int n,p;
set<ll> ans;

void dfs(int ind,int now,ll num)
{
    ans.insert(num);
    if(now < prime[ind])
        return;
    dfs(ind,now-prime[ind],num*prime[ind]%p);  //分解这个
    dfs(ind+1,now,num);  //不分解这个
}

int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d%d",&n,&p);
        ans.clear();
        dfs(0,n,1);
        printf("%d\n",ans.size());
    }
    return 0;
}