FZU 1627 Revival's road

矩阵快速幂。

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<iostream>
using namespace std;
typedef long long LL;
const double pi=acos(-1.0);
void File()
{
    freopen("D:\\in.txt","r",stdin);
    freopen("D:\\out.txt","w",stdout);
}

int MOD=;
int T,n,m,k;

struct Matrix
{
    int A[][];
    int R, C;
};

Matrix X, Y, Z;

Matrix cheng(Matrix a, Matrix b)
{
    Matrix c;

    int i, j, k;
    for (i = ; i <= a.R; i++)
        for (j = ; j <= b.C; j++)
        {
            c.A[i][j]=;
            for (k = ; k <= a.C; k++)
                c.A[i][j] = (c.A[i][j] + (a.A[i][k] * b.A[k][j]) % MOD) % MOD;
        }

    c.R = a.R; c.C = b.C;

    return c;
}

void init()
{
    memset(X.A, , sizeof X.A);
    memset(Y.A, , sizeof Y.A);

    Y.R = n; Y.C = n;
    for (int i = ; i <= n; i++) Y.A[i][i] = ;

    for(int i=;i<=m;i++)
    {
        int a,b; scanf("%d%d",&a,&b);
        X.A[a][b]=;
    }

    X.R = n; X.C = n;
}

void work()
{
    while (k)
    {
        if (k %  == ) Y = cheng(Y,X);
        k = k >> ;
        X = cheng(X,X);
    }
    printf("%d\n",Y.A[][n]);
}

int main()
{
    while(~scanf("%d%d%d",&n,&m,&k))
    {
        init();
        work();
    }
    return ;
}