bzoj2875: [Noi2012]随机数生成器

矩阵乘法。

x[n] = {x[0],1} * ( {a,0} ^ n )

{b,1}

写成这样谁能看懂。。。。

noi里的大水题。我居然

#include<cstdio>
#include<algorithm>
#include<cstring>
#include<iostream>
#define LL long long
using namespace std;
const int maxn = ;

LL a,b,mod,g,x,n,ans;

LL mul(long long a,long long b) {
        a%=mod; b%=mod;
        long long res=;
        while(b) {
            if(b&) res=(res+a)%mod;
            a=(a+a)%mod;
            b>>=;
        }
        return res;
    }

struct Matrix {
    const static LL n = ;
    LL a[maxn][maxn];

    inline LL* operator [] (int x) {
        return a[x];
    }

    Matrix operator* (Matrix b) {
        Matrix res;
        for(int i=;i<=n;i++)
        for(int j=;j<=n;j++)
        for(int k=;k<=n;k++)
            res[i][k]=(res[i][k]+mul(a[i][j],b[j][k]))%mod;
        return res;
    }

    void build() {
        for(int i=;i<=n;i++) a[i][i]=;
    }

    Matrix operator^ (long long e) {
        Matrix res,tmp=*this;
        res.build();
        while(e) {
            if(e&) res=res*tmp;
            tmp=tmp*tmp;
            e>>=;
        }
        return res;
    }

    Matrix () {
        memset(a,,sizeof(a));
    }
}res;

int main() {
    cin >> mod >> a >> b >> x >> n >> g;
    res[][]=a; res[][]=b; res[][]=;
    res=res^n;
    ans=(mul(x,res[][])+res[][])%mod;
    ans=ans%g;
    cout << ans <<'\n';
    return ;
}

都1A了。