#include<iostream>
#include<fstream>
#include <sstream> 

using namespace std;
 
void LU(int n,double *a,double *b,double *c,double d,double e,double *pointx,double *pointy)
{
	double *f=new double[n+1];
	double *g=new double[n+1];
	double *h=new double[n+1];
	double *k=new double[n+1];
	//求解得到h[],f[]
	h[1]=b[1];
	for(int i=1;i<n-1;i++)
	{
		f[i]=a[i]/h[i];
		h[i+1]=b[i+1]-f[i]*c[i];
	}
	//求解得到g[]和f[n-1]
	g[1]=d/h[1];
	for(int i=1;i<n-2;i++)
	{
		g[i+1]=-g[i]*c[i]/h[i+1];
	}
	f[n-1]=(a[n-1]-g[n-2]*c[n-2])/h[n-1];
	//求解得到k[]和h[n]
	k[1]=e;
	for(int i=1;i<n-2;i++)
	{
		k[i+1]=-f[i]*k[i];
	}
	k[n-1]=c[n-1]-f[n-2]*k[n-2];
	double gk_sum=0;
	for(int i=1;i<n-1;i++)
	{
		gk_sum=gk_sum+g[i]*k[i];
	}
	h[n]=b[n]-gk_sum-f[n-1]*c[n-1];
	//矩阵求解过程
	//追的过程
	double *y=new double[n+1];
	double *x=new double[n+1];
	x[0]=6*pointx[n-1];
	y[0]=6*pointy[n-1];
	for(int i=0;i<n-2;i++)
	{
		x[i+1]=6*pointx[i]-f[i+1]*x[i];
		y[i+1]=6*pointy[i]-f[i+1]*y[i];
	}
	double gx_sum=0,gy_sum=0;
	for(int i=0;i<n-2;i++)
	{
		gx_sum=gx_sum+g[i+1]*x[i];
		gy_sum=gy_sum+g[i+1]*y[i];
	}
	x[n-1]=6*pointx[n-2]-gx_sum-f[n-1]*x[n-2];
	y[n-1]=6*pointy[n-2]-gy_sum-f[n-1]*y[n-2];
	//赶的过程
	double *px=new double[n+2];
	double *py=new double[n+2];
	px[n-1]=x[n-1]/h[n];
	px[n-2]=(x[n-2]-k[n-1]*px[n-1])/h[n-1];
	py[n-1]=y[n-1]/h[n];
	py[n-2]=(y[n-2]-k[n-1]*py[n-1])/h[n-1];
	for(int i=n-3;i>=0;i--)
	{
		px[i]=(x[i]-c[i+1]*px[i+1]-k[i+1]*px[n-1])/h[i+1];
		py[i]=(y[i]-c[i+1]*py[i+1]-k[i+1]*py[n-1])/h[i+1];
	}
	px[n]=px[0];px[n+1]=px[1];
	py[n]=py[0];py[n+1]=py[1];
	//将排序后的端点写入到文件中
	ofstream ftxt("e:\\me.txt");
	if(!ftxt)
	{
		cout<<"创建文件失败！请检查文件写路径是否正确！"<<endl;
		return;
	}
	//ftxt.open("e:\\me.txtme.txt",ios::trunc);//打开文件之前清空文件
	ftxt<<n<<endl;
	int count=0;
	for(int i=0;i<n;i++)
	{
		//cout<<vecCorners[i]<<endl;
		ftxt<<px[i]<<","<<py[i]<<endl;
		count++;
	}
	for(int i=0;i<n;i++)
	{
		//cout<<vecCorners[i]<<endl;
		ftxt<<pointx[i]<<","<<pointy[i]<<endl;
	}
	ftxt.close();
	cout<<"写入文件成功！共写入："<<count<<"个特征点"<<endl;
	delete [] f,k,g,h,x,y,px,py;
}
void Equalication()
{
	ifstream intxt("e:\\me.txt");
	if(!intxt)
	{
		cout<<"文件打开错误，请查看文件路径是否错误！"<<endl;
		return;
		intxt.close();
	}
	int j=0;
	string cnum;
	int inum;
	//求得到的点数
	getline(intxt,cnum);
	istringstream iss(cnum);  
	iss >> inum;
	double *pointx=new double[inum+1];
	double *pointy=new double[inum+1];
	
	string point_str;
	string xstr,ystr;
	float x,y;
	while(getline(intxt,point_str))
	{
		xstr=point_str.substr(0,point_str.find_last_of(","));
		ystr=point_str.substr(point_str.find_first_of(",")+1);
		istringstream xss(xstr);  
		istringstream yss(ystr); 
		xss >> x;
		yss >> y;
		pointx[j]=x;
		pointy[j]=y;
		//cout<<pointx[c]<<pointy[c]<<endl;
		j++;
	}
	intxt.close();
	//初始化
	//int inum=12;
	//double pointx[12]={-10,-50,-50,-10,-20,20,10,50,50,10,20,-20};
	//double pointy[12]={10,20,-20,-10,-50,-50,-10,-20,20,10,50,50};
	///*double pointx[5]={-100,100,100,100,20};
	//double pointy[5]={100,50,-100,100,80};*/
	double *a=new double[inum];
	double *b=new double[inum];
	double *c=new double[inum];
	int d=1,e=1;
	for(int i=1;i<=inum;i++)
	{
		b[i]=4;
		if((i+1)<=inum)
		{
			a[i]=1;c[i]=1;
		}
	}
	LU(inum,a,b,c,d,e,pointx,pointy);
}