poj 1995 快速幂（裸）

最新推荐文章于 2020-03-28 20:40:35 发布

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原文链接：http://www.cnblogs.com/ZZUGPY/p/8479607.html

本文介绍了一种基于快速幂运算的游戏算法，该游戏的目标是计算所有玩家选择的数对经过快速幂运算后的总和，并求得该总和对给定数M取模的结果。文中提供了一个C++实现示例，用于解决这个问题。

Raising Modulo Numbers

Time Limit: 1000MS		Memory Limit: 30000K
Total Submissions: 9218		Accepted: 5611

Description

People are different. Some secretly read magazines full of interesting girls' pictures, others create an A-bomb in their cellar, others like using Windows, and some like difficult mathematical games. Latest marketing research shows, that this market segment was so far underestimated and that there is lack of such games. This kind of game was thus included into the KOKODáKH. The rules follow:

Each player chooses two numbers Ai and Bi and writes them on a slip of paper. Others cannot see the numbers. In a given moment all players show their numbers to the others. The goal is to determine the sum of all expressions Ai^Bi from all players including oneself and determine the remainder after division by a given number M. The winner is the one who first determines the correct result. According to the players' experience it is possible to increase the difficulty by choosing higher numbers.

You should write a program that calculates the result and is able to find out who won the game.

Input

The input consists of Z assignments. The number of them is given by the single positive integer Z appearing on the first line of input. Then the assignements follow. Each assignement begins with line containing an integer M (1 <= M <= 45000). The sum will be divided by this number. Next line contains number of players H (1 <= H <= 45000). Next exactly H lines follow. On each line, there are exactly two numbers Ai and Bi separated by space. Both numbers cannot be equal zero at the same time.

Output

For each assingnement there is the only one line of output. On this line, there is a number, the result of expression

(A₁^B₁+A₂^B₂+ ... +A_H^B_H)mod M.

Sample Input

3
16
4
2 3
3 4
4 5
5 6
36123
1
2374859 3029382
17
1
3 18132

Sample Output

2
13195
13

直接裸快速幂就能过了

#include<iostream>
using namespace std;

int pow1(int a,int b,int m)
{
    int res = 1;
    a %= m;
    while(b)
    {
        if(b&1)
            res = res*a%m;
        a = a*a%m;
        b >>= 1;    
    }    
    return res;
}

int main()
{
    int n;
    int mod,m,sum; 
    int a,b;
    cin>>n;
    while(n--)
    {
        cin>>mod>>m;
        sum = 0;
        for(int i = 0;i<m;i++)
        {
            cin>>a>>b;
            sum = (sum + pow1(a,b,mod))%mod;
        }
        cout<<sum%mod<<endl;
    }
}