HDU3706 Second My Problem First

看似一道数论题，是道比较明显的单调队列题。

#include <iostream>
#include <string>
#include <stdio.h>
#include <stdlib.h>
#include <algorithm>
#include <string.h>
#include <vector>
#include <math.h>
#include <map>
#include <time.h>
#include <queue>
#include <set>
using namespace std;

typedef __int64 int64;

const int MAX = 1e7 + 5;

int n, A, B, h, t;
int S[MAX];
int q[MAX][2];

void ready()
{
    S[0] = 1;
    for(int i = 1; i <= n; i++)
    {
        S[i] = (int64)(S[i - 1]) * A % B;
    }

    //init the queue
    h = 0, t = 0;
}

void insert(int key, int value)
{
    while(h < t && value <= q[t - 1][1])  t--;
    q[t][0] = key;
    q[t++][1] = value;
}

int64 go()
{
    int64 res = 1;
    for(int i = 1; i <= n; i++)
    {
        //printf("@%d %d\n", i, S[i]);
        insert(i, S[i]);
        if(i - q[h][0] > A)  h++;
        res = res * q[h][1] % B;
    }
    return res;
}

int main()
{
    while(scanf("%d%d%d", &n, &A, &B) != EOF)
    {
        ready();
        printf("%I64d\n", go());
    }
}