HDU-2256 Problem of Precision (神奇)

好强啊,像我这种就会以为是直接double乘一乘,我好菜。

/*
求
(5+2sqrt(6))^n
[x+y*sqrt(6)]*[5+2sqrt(6)]=5x+12y+(5y+2x)
x	5 12
y	2 5
*/ 
#include<bits/stdc++.h>
using namespace std;
#define rep(i,x,y) for(int i=x;i<=y;i++)
#define per(i,x,y) for(int i=x;i>=y;i--)
typedef long long LL;
int t,n,k,p=1024;
struct mat{
	int a[5][5];
	void init(){memset(a,0,sizeof(a));}
};
int add(int x,int y){
	return ((x+y)%p+p)%p;
}
mat mul(mat x,mat y){
	mat z;z.init();
	rep(i,1,2) rep(j,1,2) rep(k,1,2)
		z.a[i][j]=add(z.a[i][j],1ll*x.a[i][k]*y.a[k][j]%p);
	return z;
} 
mat power(mat x,int y){
	mat ret=x;y--;
	while(y){
		if(y&1) ret=mul(ret,x);
		x=mul(x,x);y>>=1;
	}
	return ret;
}
int calc(int x,int y){
	return add(0,2*x-1);
}
int main(){
	mat x,y;
	cin>>t;
	x.init();y.init();
	x.a[1][1]=5,x.a[2][1]=2;
	y.a[1][1]=5,y.a[1][2]=12;
	y.a[2][1]=2,y.a[2][2]=5;
	while(t--){
		scanf("%d",&n);
		if(n==1){
			printf("%d
",calc(x.a[1][1],x.a[2][1]));
			continue;
		}
		mat ans=mul(power(y,n-1),x);
		printf("%d
",calc(ans.a[1][1],ans.a[2][1]));
	}
	return 0;
}
qaqaq
原文地址:https://www.cnblogs.com/zdsrs060330/p/13828360.html