Matrix fast power

1. Initialize the cell matrix
2. Enter the matrix value
3. Similar to fast power matrix multiplication
4. Overloaded operation *, Used to represent matrix multiplication

#include<bits/stdc++.h>
using namespace std;
const int maxn=110;
const int mod=1e9+7;
struct mat{
    
	int m[maxn][maxn];
}unit;
int n;
void init_unit()
{
    
	for(int i=0;i<maxn;i++)
		unit.m[i][i]=1;
	return ;
}
mat operator *(mat a,mat b)
{
    
	mat ret;
	long long x;
	for(int i=0;i<n;i++){
    
		for(int j=0;j<n;j++){
    
			x=0;
			for(int k=0;k<n;k++)
				x=(x%mod+((long long)a.m[i][k]*b.m[k][j])%mod)%mod;
			ret.m[i][j]=x%mod;
		}
	}
	return ret;
}
mat pow_mat(mat a,long long y)
{
    
	mat res=unit;
	while(y)
	{
    
		if(y&1) res=res*a;
		y>>=1;
		a=a*a;
	}
	return res;
}
int main()
{
    
	long long x;
	init_unit();
	while(cin>>n>>x)
	{
    
		mat a;
		for(int i=0;i<n;i++)
			for(int j=0;j<n;j++)
				cin>>a.m[i][j];
		a=pow_mat(a,x);
		for(int i=0;i<n;i++)
			for(int j=0;j<n;j++)
				if(j+1==n) cout<<a.m[i][j]<<endl;
				else cout<<a.m[i][j]<<" ";
	}
	return 0;
}