矩阵快速幂

Posted 2020-10-19 xayata

https://www.luogu.org/problemnew/show/P3390

快速幂 + 矩阵

#include <bits/stdc++.h>

using namespace std;

#define LL long long

const LL mod = 1e9 + 7;
const int N = 110;

LL n, k;

struct JZ{
    LL m[N][N];
    JZ() {memset(m,0,sizeof m);}
    void clear() {for(int i = 1; i <= 100; i ++) m[i][i] = 1;}
};

JZ operator *(JZ a, JZ b) {
    JZ ret;
    for(int i = 1; i <= n; i ++)
        for(int j = 1; j <= n; j ++)
            for(int k = 1; k <= n; k ++)
                ret.m[i][j] = (ret.m[i][j] + a.m[i][k] * b.m[k][j]) % mod;
    return ret; 
}

JZ ksm(JZ a, LL p){
    JZ ret; ret.clear();
    while(p){
        if(p & 1) ret = ret * a;
        a = a * a;
        p >>= 1;
    }
    return ret;
}

int main()
{
    cin >> n >> k;
    JZ a;
    for(int i = 1; i <= n; i ++)
        for(int j = 1; j <= n; j ++)
            cin >> a.m[i][j];
    JZ Ans = ksm(a, k);
    
    for (int i=1; i<=n; i++,puts("")) 
        for (int j=1; j<=n; j++) 
            printf("%lld ",Ans.m[i][j]);    
    return 0;
}