hdu4686---Arc of Dream(矩阵)

Problem Description
An Arc of Dream is a curve defined by following function:

where
a0 = A0
ai = ai-1*AX+AY
b0 = B0
bi = bi-1*BX+BY
What is the value of AoD(N) modulo 1,000,000,007?

Input
There are multiple test cases. Process to the End of File.
Each test case contains 7 nonnegative integers as follows:
N
A0 AX AY
B0 BX BY
N is no more than 1018, and all the other integers are no more than 2×109.

Output
For each test case, output AoD(N) modulo 1,000,000,007.

Sample Input

1 1 2 3 4 5 6 2 1 2 3 4 5 6 3 1 2 3 4 5 6

Sample Output

4 134 1902

Author
Zejun Wu (watashi)

Source
2013 Multi-University Training Contest 9

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很明显也是要用矩阵来求的
an*bn = (an-1 * Ax + Ay) * (bn-1 * Bx + By)
展开以后得到4项
(an-1 * bn-1) * Ax * Bx
an-1 * Ax * By
bn-1 * Bx * Ay
Ay * By
利用这些就可以构造出递推求an * bn的矩阵了
,但是这里要求和,所以再加一列就行了

得到一个5 * 5的矩阵
AX*BX 0 0 0 AX*BX
AX*BY AX 0 0 AX*BY
BX*AY 0 BX 0 BX*AY
AY*BY AY BY 1 AY*BY
0 0 0 0 1

注意n是0的话,输出0

/************************************************************************* > File Name: hdu4686.cpp > Author: ALex > Mail: [email protected] > Created Time: 2015年03月12日 星期四 16时21分07秒 ************************************************************************/

#include <map>
#include <set>
#include <queue>
#include <stack>
#include <vector>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;

const double pi = acos(-1.0);
const int inf = 0x3f3f3f3f;
const double eps = 1e-15;
typedef long long LL;
typedef pair <int, int> PLL;

const int mod = 1000000007;

class MARTIX
{
    public:
        LL mat[10][10];
        MARTIX();
        MARTIX operator * (const MARTIX &b)const;
        MARTIX& operator = (const MARTIX &b);
};

MARTIX::MARTIX()
{
    memset (mat, 0, sizeof(mat));
}

MARTIX MARTIX :: operator * (const MARTIX &b)const
{
    MARTIX ret;
    for (int i = 0; i < 5; ++i)
    {
        for (int j = 0; j < 5; ++j)
        {
            for (int k = 0; k < 5; ++k)
            {
                ret.mat[i][j] += this -> mat[i][k] * b.mat[k][j];
                ret.mat[i][j] %= mod;
            }
        }
    }
    return ret;
}

MARTIX& MARTIX :: operator = (const MARTIX &b)
{
    for (int i = 0; i < 5; ++i)
    {
        for (int j = 0; j < 5; ++j)
        {
            this -> mat[i][j] = b.mat[i][j];
        }
    }
    return *this;
}

MARTIX fastpow(MARTIX ret, LL n)
{
    MARTIX ans;
    for (int i = 0; i < 5; ++i)
    {
        ans.mat[i][i] = 1;
    }
    while (n)
    {
        if (n & 1)
        {
            ans = ans * ret;
        }
        ret = ret * ret;
        n >>= 1;
    }
    return ans;
}

void Debug(MARTIX A)
{
    for (int i = 0; i < 5; ++i)
    {
        for (int j = 0; j < 5; ++j)
        {
            printf("%lld ", A.mat[i][j]);
        }
        printf("\n");
    }
}

int main ()
{
    LL A0, AX, AY, B0, BX, BY, n;
    while (~scanf("%lld", &n))
    {
        scanf("%lld%lld%lld", &A0, &AX, &AY);
        scanf("%lld%lld%lld", &B0, &BX, &BY);
        MARTIX A;
        if (!n)
        {
            printf("0\n");
            continue;
        }
        A.mat[0][0] = A.mat[0][4] = AX * BX % mod;
        A.mat[1][0] = A.mat[1][4] = AX * BY % mod;
        A.mat[1][1] = AX;
        A.mat[2][0] = A.mat[2][4] = BX * AY % mod;
        A.mat[2][2] = BX;
        A.mat[3][0] = A.mat[3][4] = AY * BY % mod;
        A.mat[3][3] = 1;
        A.mat[3][1] = AY;
        A.mat[3][2] = BY;
        A.mat[4][4] = 1;
        MARTIX ans = fastpow(A, n - 1);
// Debug(ans);
        MARTIX F;
        F.mat[0][0] = F.mat[0][4] = A0 * B0 % mod;
        F.mat[0][1] = A0 % mod;
        F.mat[0][2] = B0 % mod;
        F.mat[0][3] = 1;
        F = F * ans;
        printf("%lld\n", F.mat[0][4]);
    } 
    return 0;
}