矩阵快速幂模板

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int Matr = 4;
const ll mod = 1e9 + 7;

class mat
{
public:
	ll a[Matr][Matr], size;
	mat(int len){
		size = len;
		memset(a, 0, sizeof(a));
	}
	void print()
	{
		for (int i = 1;i <= size;i++)
		{
			for (int j = 1;j <= size;j++)
				printf("%lld ", a[i][j]);
			printf("\n");
		}
	}
	void operator =(mat m)
	{
		for (int i = 1;i <= size;i++)
			for (int j = 1;j <= size;j++)
				a[i][j] = m.a[i][j];
	}
};
mat operator *(mat m1, mat m2)
{
	mat ans(m1.size);
	for (int i = 1;i <= m1.size;i++)
		for (int j = 1;j <= m2.size;j++)
			if (m1.a[i][j])
				for (int k = 1;k <= m1.size;k++)
					ans.a[i][k] = (ans.a[i][k] + m1.a[i][j] * m2.a[j][k]) % mod;
	return ans;
}
mat quickmulti(mat m, int n)
{
	mat ans(m.size);
	for (int i = 1;i <= m.size;i++)
			ans.a[i][i] = 1;
	while (n)
	{
		if (n & 1)ans = m * ans;
		m = m * m;
		n >>= 1;
	}
	return ans;
}