十字链表

#include <iostream>
#include <vector>
#include <fstream>
#include <cassert>

using namespace std;

template<class InfoType, class VertexType>
class OLGraph
{
	struct ArcBox
	{//弧结点
		size_t tail_vex;//弧尾
		size_t head_vex;//弧头
		ArcBox *hlink;//指向弧头相同的下一条弧
		ArcBox *tlink;//指向弧尾相同的下一条弧
		InfoType info;//弧结点存储的信息
	};
	struct VexNode
	{//顶点结点
		VertexType data;//顶点值
		ArcBox *firstin;//以该顶点为弧头的第一个弧结点
		ArcBox *firstout;//以该顶点为弧尾的第一个弧结点
	};

public:
	OLGraph();//输入构造图
	OLGraph(fstream &file);//从文件构造图
	InfoType get_info(VertexType v1, VertexType v2);//获取两结点所在弧的信息
private:
	size_t locate_vex(VertexType v);//确定顶点值在容器中的位置
public:
	vector<VexNode> xlist;//存储顶点结点
	size_t vex_num;//顶点个数
	size_t arc_num;//弧个数
	bool IncInfo;//弧是否有附加信息
};

template<class InfoType, class VertexType>
OLGraph<InfoType, VertexType>::OLGraph()
{
	//构造有向图
	cout << "input the total of vertex number and arc number, is IncInfo true? " << endl;
	cin >> vex_num >> arc_num >> IncInfo;
	cout << "input each vertex value: " << endl;
	VexNode tmp;
	for (size_t i=0; i<vex_num; ++i)
	{
		//输入顶点的值
		cin.clear();
		cin >> tmp.data;
		tmp.firstin = tmp.firstout = NULL;
		xlist.push_back(tmp);
	}

	for (size_t k=0; k<arc_num; ++k)
	{//输入两顶点的弧
		cout << "input two points of the arc and the arcinfo" << endl;
		VertexType v1, v2;
		InfoType info;
		cin.clear();
		if (IncInfo) cin >> v1 >> v2 >> info;
		else cin >> v1 >> v2;
		size_t i = locate_vex(v1);
		size_t j = locate_vex(v2);
		ArcBox *p = new ArcBox;
		//*p = {i, j, xlist[j].firstin, xlist[i].firstout, NULL};
		p->tail_vex = i;
		p->head_vex = j;
		p->hlink = xlist[j].firstin;
		p->tlink = xlist[i].firstout;
		p->info = info;
		xlist[j].firstin = xlist[i].firstout = p;
	}
}

template<class InfoType, class VertexType>
size_t OLGraph<InfoType, VertexType>::locate_vex(VertexType v)
{
	size_t i=0;
	size_t length = xlist.size();
	for (; i<length; ++i)
	{
		if (xlist[i].data == v) return i;
	}
	exit(1);
}

template<class InfoType, class VertexType>
InfoType OLGraph<InfoType, VertexType>::get_info(VertexType v1, VertexType v2)
{
	size_t i = locate_vex(v1);
	size_t j = locate_vex(v2);
	ArcBox *p = xlist[i].firstout;
	while (NULL != p)
	{
		if (p->head_vex == j) return p->info;
		else p = p->tlink;
	}
	exit(2);
}

template<class InfoType, class VertexType>
OLGraph<InfoType, VertexType>::OLGraph(fstream &file)
{
	//从文件构造有向图
	if (file.fail()) exit(3);
	//cout << "input the total of vertex number and arc number, is IncInfo true? " << endl;
	file >> vex_num >> arc_num >> IncInfo;
	//cout << "input each vertex value: " << endl;
	VexNode tmp;
	for (size_t i=0; i<vex_num; ++i)
	{
		//输入顶点的值
		//cin.clear();
		file >> tmp.data;
		tmp.firstin = tmp.firstout = NULL;
		xlist.push_back(tmp);
	}

	for (size_t k=0; k<arc_num; ++k)
	{//输入两顶点的弧
		//cout << "input two points of the arc and the arcinfo" << endl;
		VertexType v1, v2;
		InfoType info;
		//cin.clear();
		if (IncInfo) file >> v1 >> v2 >> info;
		else file >> v1 >> v2;
		size_t i = locate_vex(v1);
		size_t j = locate_vex(v2);
		ArcBox *p = new ArcBox;
		//*p = {i, j, xlist[j].firstin, xlist[i].firstout, NULL};
		p->tail_vex = i;
		p->head_vex = j;
		p->hlink = xlist[j].firstin;
		p->tlink = xlist[i].firstout;
		p->info = info;
		xlist[j].firstin = xlist[i].firstout = p;
	}
}