[Logo P3390] Matrix fast power template [Matrix multiplication]

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Problem solving ideas

Mind your blog! ! !

For matrix multiplication ideas, please see >link

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Code

#include<algorithm>
#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
const long long INF=1000000007;
long long n,k;
using namespace std;
struct c{
    
    
	long long n,m;
	long long a[200][200];
}A,B,CC;
c operator *(c A,c B){
    
    
	c C;
	C.n=A.n,C.m=B.m;
	for(int i=1;i<=C.n;i++)
		for(int j=1;j<=C.m;j++)
			C.a[i][j]=0;
	for(int k=1;k<=A.m;k++)
	{
    
    
		for(int i=1;i<=C.n;i++)
			for(int j=1;j<=C.m;j++)
				C.a[i][j]=(C.a[i][j]+(A.a[i][k]*B.a[k][j])%INF)%INF;
	}	
	return C;
}
void poww(long long x){
    
    
	if(x==1)
	{
    
    
		B=A;
		return; 
	}
	poww(x>>1);
	B=B*B;
	if(x&1)
		B=B*A;
	
}
int main(){
    
    
	scanf("%lld%lld",&n,&k);
	A.n=n,A.m=n;
	for(int i=1;i<=n;i++)
		for(int j=1;j<=n;j++)
			scanf("%lld",&A.a[i][j]);
	if(k==1)
	{
    
    
		for(int i=1;i<=n;i++)
		{
    
    
			for(int j=1;j<=n;j++)
				printf("%lld ",A.a[i][j]);
			printf("\n");
		}
		return 0;
	}
	poww(k);
	for(int i=1;i<=n;i++)
	{
    
    
		for(int j=1;j<=n;j++)
			printf("%lld ",B.a[i][j]);	
		printf("\n");
	}
}