Color

http://poj.org/problem?id=2154

long long 超时， int 过了。。。

#include <iostream>
#include <cstring>
#include <cmath>
#include <cstdio>
#include <algorithm>
using namespace std;
#define LL long long
int p;
int quickpow(int a, int b, int mod){
    int temp = a % mod, res = 1;
    while(b){
        if(b & 1) res = res * temp % mod;
        b >>= 1;
        temp = temp * temp % mod;
    }
    return res;
}
const int maxn = 36010;
int pri[maxn];
int cnt;
void init(){
    cnt = 0;
    memset(pri, 0, sizeof(pri));
    for(int i = 2; i < maxn; i++){
        if(!pri[i]){
            pri[cnt++] = i;
            for(int j = i * i; j < maxn; j += i) pri[j] = 1;
        }
    }
}
int phi(int n){
    int res = n;
    for(int i = 0; pri[i] * pri[i] <= n; i++) {
        if(n % pri[i] == 0){
            res = res - res / pri[i];
            while(n % pri[i] == 0) n /= pri[i];
        }
    }
    if(n > 1){
        res = res - res / n;
    }
    return res % p;
}
int main(){
    int c, n;
    //freopen("in.txt", "r", stdin);
    int t;
    init();
    scanf("%d", &t);
    while(t--){
        scanf("%d %d", &n, &p);
        int ans = 0;
        c = n;
        for(int i = 1 ; i * i <= n; i++){
            if(i * i == n) ans = (ans + quickpow(c, i - 1, p) * phi(i)) % p;
            else if(n % i == 0){
                ans = (ans + quickpow(c, i - 1, p) * phi(n / i) + quickpow(c, n / i - 1, p) * phi(i)) % p;
            }
        }
        printf("%d
", ans);
    }
}