【挖坟】HDU3205 Factorization

分圆多项式

问题在于精度貌似出了一些奇怪的问题。。。

【输出也写的有问题QAQ】

完全不会处理了 加上全网没有题解T^T

挖个坑以后补。。

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
#define inf 20021225
#define ll long long
#define mxn 10100
#define pa pair<int,int>
#define mp make_pair
#define db long double
using namespace std;

int d[mxn][mxn];int m[mxn];
bool vis[mxn];
// x -> n y -> pow

template<typename T>
inline T labs( const T & x ){return x<0?-x:x;}
 
template<typename T>
inline int sgn( const T & x ){return x<0?-1:(x?1:0);}
 
inline int d_round( const db & x ){return (int)(sgn(x)*(labs(x)+0.50001));}

const db pi=acos(-1.0);
struct complex
{
    db x,y;
    complex(){}
    complex(db _x,db _y){x=_x,y=_y;}
};
complex tmp[mxn],fin[mxn];
complex operator +(complex a,complex b){return complex(a.x+b.x,a.y+b.y);}
complex operator -(complex a,complex b){return complex(a.x-b.x,a.y-b.y);}
complex operator *(complex a,complex b){return complex(a.x*b.x-a.y*b.y,a.x*b.y+b.x*a.y);}
int gcd(int x,int y)
{
	return y==0?x:gcd(y,x%y);
}
void calc(int n)
{
	if(vis[n])	return;
	vis[n]=1;
	for(int i=0;i<n;i++)	tmp[i]=complex(0,0);
	tmp[0]=complex(1,0); int c=1;
	//printf("--------%d---------
",n);
	for(int i=1;i<n;i++)
	{
		if(gcd(i,n)!=1)		continue;
		//printf("%d %d
",i,n);
		db qaq=(db)i/(db)n*2.0*pi;// printf("%lf
",qaq/pi);
		for(int j=c;j;j--)
		{
			tmp[j] = tmp[j-1] - tmp[j] * complex(cos(qaq),sin(qaq));
			//if(i<10)	printf("%lf ",tmp[j]);
		}
		tmp[0] = complex(0,0) - tmp[0] * complex(cos(qaq),sin(qaq));
		//if(i<10)	printf("
");
		c++;
	}
	m[n]=c;
	for(int i=c;~i;i--)
	{
		d[n][i]=d_round(tmp[i].x);
		//printf("%lf ",tmp[i].x);
	}
}

void get(int n)
{
	int f;
	for(int i=1;i<=n;i++)
	{
		if(n%i==0)
		{
			calc(i);f=0;
			for(int j=m[i];j>1;j--)	
			{
				if(d[i][j])
				{
					if(!f)	printf("("),f=1;
					if(d[i][j]<-1)	printf("%dx^%d",d[i][j],j);
					else if(abs(d[i][j])==1)
					{
						if(f==1)	printf("x^%d",j);
						else if(d[i][j]==-1)	printf("-x^%d",j);
						else	printf("+x^%d",j);
					}
					else	printf("+%dx^%d",d[i][j],j);
					f=2;
				}
			}
			if(d[i][1])
			{
				if(!f)	printf("("),f=1;
				if(d[i][1]<-1)	printf("%dx",d[i][1]);
				else if(abs(d[i][1])==1)
				{
					if(f==1)	printf("x");
					else if(d[i][1]==-1)	printf("-x");
					else	printf("+x");
				}
				else	printf("+%dx",d[i][1]);
			}
			if(d[i][0]>0)	printf("+%d)",d[i][0]);
			else	printf("%d)",d[i][0]);
		}
	}
	printf("
");
	//printf("%lf
",cos(4.0/11.0*pi)+cos(6.0/11.0*pi));
}

int n;
int main()
{
	vis[1]=vis[2]=1;
	m[1]=m[2]=2;
	d[1][1]=d[2][1]=1;
	d[1][0]=-1;d[2][0]=1;
	while(scanf("%d",&n)&&n)
		get(n);
	return 0;
}