hdu 1452 数论

这题比较好，考查了数论的许多知识，包括一个数所有因子的和的形式，以及同余公式(除法的同余公式，即求同余下的逆元)等，网上好多讨论的，这里就不再啰嗦了，直接贴代码。

/*
 * hdu1452/win.cpp
 * Created on: 2011-10-24
 * Author    : ben
 */
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <ctime>
#include <iostream>
#include <algorithm>
#include <queue>
#include <set>
#include <map>
#include <stack>
#include <string>
#include <vector>
#include <deque>
#include <list>
#include <functional>
#include <numeric>
#include <cctype>
using namespace std;
const int MOD = 29;
typedef long long LL;
int modular_exp(int a, int b, int c) {
    LL res, temp;
    res = 1 % c, temp = a % c;
    while (b) {
        if (b & 1) {
            res = res * temp % c;
        }
        temp = temp * temp % c;
        b >>= 1;
    }
    return (int) res;
}

int main() {
#ifndef ONLINE_JUDGE
    freopen("data.in", "r", stdin);
#endif
    int x;
    int firstpart, secondpart, thirdpart;
    while (scanf("%d", &x) == 1 && x > 0) {
        firstpart = modular_exp(2, 2 * x + 1, MOD) - 1;
        secondpart = modular_exp(3, x + 1, MOD) - 1;
        secondpart = (secondpart * 15) % MOD;
        thirdpart = modular_exp(167, x + 1, MOD) - 1;
        thirdpart = (thirdpart * 18) % MOD;
        int ans = firstpart * secondpart * thirdpart;
        ans %= MOD;
        printf("%d\n", ans);
    }
    return 0;
}