HDU - 4291 循环节
还有这种操作?
#include<bits/stdc++.h>
#define rep(i,j,k) for(register int i=j;i<=k;i++)
#define println(a) printf("%lld\n",(ll)a)
using namespace std;
typedef long long ll;
ll mod = 183120;
ll read(){
ll x=0,f=1;register char ch=getchar();
while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
return x*f;
}
struct Matrix{
ll mt[9][9],r,c;
void init(int rr,int cc,bool flag=0){
r=rr;c=cc;
memset(mt,0,sizeof mt);
if(flag) rep(i,1,r) mt[i][i]=1;
}
Matrix operator * (Matrix rhs){
Matrix ans; ans.init(r,rhs.c);
rep(i,1,r){
rep(j,1,rhs.c){
int t=max(r,rhs.c);
rep(k,1,t){
ans.mt[i][j]+=(mt[i][k]*rhs.mt[k][j])%mod;
ans.mt[i][j]=(ans.mt[i][j])%mod;
}
}
}
return ans;
}
};
Matrix fpw(Matrix A,ll n){
Matrix ans;ans.init(A.r,A.c,1);
while(n){
if(n&1) ans=ans*A;
n>>=1;
A=A*A;
}
return ans;
}
ll n;
ll base[3][3]={
{0,0,0},
{0,3,1},
{0,1,0}
};
int main(){
while(cin>>n){
mod=183120;
Matrix A; A.init(2,2);
rep(i,1,2)rep(j,1,2) A.mt[i][j]=base[i][j];
Matrix res=fpw(A,n);
mod=222222224;
res=fpw(A,res.mt[1][2]%183120);
mod=1e9+7;
res=fpw(A,res.mt[1][2]%222222224);
println(res.mt[1][2]);
}
return 0;
}