SPOJ AMR10I Dividing Stones

http://www.spoj.pl/problems/AMR10I

数论递归＋处理

#include <cstdio>#include <iostream>#include <algorithm>#include <cmath>#include <cstring>#include <map>using namespace std;#define foru(i, a, b) for(int i=(a); i<=(b); i++)#define ford(i, a, b) for(int i=(a); i>=(b); i--)#define clr(a) memset(a, 0, sizeof(a))typedef long long ll;ll p;int n, m, num, tot;int pri[20] = {1, 2, 3, 5, 7, 11, 13,            17, 19, 23, 29, 31, 37,            41, 43, 47, 53, 59, 61,            67};    map<ll,int> s;void dfs(int d, int sum, ll c){    if (sum < 0) return;    s[c]=1;    ford(i, d, 1){        dfs(i, sum-pri[i], (c*pri[i])%p);    }}int main(){  //  freopen("date.in", "r", stdin);    int T; scanf("%d", &T);    while (T--){        s.clear();        scanf("%d%lld", &n, &p);        dfs(19, n, 1ll);        printf("%d\n", s.size());    }    return 0;}