一个通用的图类

Graph.h

#pragma once
#include <iostream>
#include <vector>
#include <algorithm>
#include <stack>

using namespace std;
struct Edge
{
	int Start = -1;
	int End = -1;
	int K = 0;
	Edge(int s, int e) :Start(s), End(e),K(0) {}
	Edge(int s, int e,int k) :Start(s), End(e),K(k) {}
};

bool operator < (const Edge& e1, const Edge& e2)
{
	return (e1.Start == e2.Start ? e1.End < e2.End : e1.Start < e2.Start);
}

class Graph
{
protected:
	int m_EdgesNumber;
	int m_NodesNumber;
	vector<Edge> m_Edges;
	vector<int> m_NodesHead;
public:
	Graph()
	{
		m_EdgesNumber = 0;
		m_NodesNumber = 0;
	}
	void InitEdges()
	{
		for (int i = 0; i < m_EdgesNumber; i++)
		{
			m_Edges.push_back(Edge(-1,-1));
		}
	}
	void InitNodesHead()
	{
		for (int i = 0; i < m_NodesNumber; i++)
		{
			m_NodesHead.push_back(m_NodesNumber);
		}
		int buff = -1;
		for (size_t i=0;i<m_Edges.size();i++)
		{
			if (m_Edges[i].Start != buff)
			{
				buff = m_Edges[i].Start;
				m_NodesHead[buff] = i;
			}
		}
	}
	int GetNodesEdgesNumber(int node)
	{
		if (m_NodesHead[node] == -1)
			return 0;
		else
		{
			if (node == m_NodesNumber - 1)
			{
				return (m_NodesNumber - m_NodesHead[node]);
			}
			else
			{
				return (m_NodesHead[node + 1] - m_NodesHead[node]);
			}
		}
	}
	vector<int> GetNodesEdges(int node)
	{
		int head = m_NodesHead[node];
		if (head == -1)
			return vector<int>();
		else
		{
			int size = GetNodesEdgesNumber(node);
			if (size == 0)
			{
				return vector<int>();
			}
			else
			{
				vector<int> re;
				for (int i = m_NodesHead[node]; i < m_NodesHead[node] + size; i++)
				{
					re.push_back(m_Edges[i].End);
				}
				return re;
			}
		}
	}
	int GetNodesK(int from, int to)
	{
		int head = m_NodesHead[from];
		if (head == -1)
			return -1;
		else
		{
			for (int i = head; i < head + GetNodesEdgesNumber(from); i++)
			{
				if (m_Edges[i].End == to)
					return m_Edges[i].K;
			}
			return -1;
		}
	}
	virtual void Read()
	{
		cin >> m_NodesNumber >> m_EdgesNumber;
		InitEdges();
		for (Edge& i : m_Edges)
		{
		//	cin >> i.Start >> i.End>>i.K;
			cin >> i.Start >> i.End;
		}
		sort(m_Edges.begin(), m_Edges.end());
		InitNodesHead();
	}
};