深度优先搜索应用_深度优先生成树&&割点判断

#include <vector>
#include <map>
#include <utility>
#include <cassert>
#include <iostream>
#include <cmath>
using namespace std;

namespace dfst
{
	const static int INVALID_VERTEX = -1;

	typedef struct _Node
	{
		int v;
		int v_parent;
		bool invested;

		_Node( int _v=INVALID_VERTEX, int _v_parent=INVALID_VERTEX, bool _invested=false )
			:v(_v), v_parent(_v_parent), invested(_invested)
		{}
	}Node, *pNode;

	vector<vector<int> > vGraph;
	vector<Node> vDFSTree;
	int iTreeSize;

	void InitTree(void)
	{
		iTreeSize = vGraph.size();
		vDFSTree.clear();
		vDFSTree.resize( iTreeSize );
	}

	void dfs(int src)
	{
		vDFSTree[src].invested = true;
		vDFSTree[src].v = src;
		for ( vector<int >::iterator it=vGraph[src].begin(); it!=vGraph[src].end(); ++it )
		{
			if ( !vDFSTree[*it].invested )
			{
				cout << *it <<" ";
				vDFSTree[*it].v_parent = src;
				dfs( *it );
			}
		}
	}

	void PrintGraph(void)
	{
		int i(0);
		for ( vector<vector<int> >::iterator itvv=vGraph.begin(); itvv!=vGraph.end(); ++itvv )
		{
			cout << i++ << ": ";
			for ( vector<int >::iterator itv=itvv->begin(); itv!=itvv->end(); ++itv )
				cout << *itv << " ";
			cout << endl;
		}
	}
	void PrintDFSTree(void)
	{
		for ( int i=0; i<iTreeSize; ++i )
			cout << vDFSTree[i].v_parent << "-->" << vDFSTree[i].v << endl;
	}

	void PrintAll(void)
	{
		cout << "depth-first spanning tree:" << endl;
		PrintGraph();
		PrintDFSTree();
	}
};

namespace dfst_ex
{
	const static int INVALID_VERTEX = -1;
	const static int INVALID_VALUE = -1;

	typedef struct _Node
	{
		int v;
		int v_parent;
		int num;
		int low;
		bool invested;

		_Node(	int _v=INVALID_VERTEX, int _v_parent=INVALID_VERTEX, 
				int _num=INVALID_VALUE, int _low=INVALID_VALUE, bool _invested=false )
			:v(_v), v_parent(_v_parent), num(_num), low(_low), invested(_invested)
		{}
	}Node, *pNode;

	vector<vector<int> > vGraph;
	vector<Node> vDFSTree;
	map<int, int > mArticulationPoint;
	int iTreeSize;

	void InitTree(void)
	{
		iTreeSize = vGraph.size();
		vDFSTree.clear();
		vDFSTree.resize( iTreeSize );
		mArticulationPoint.clear();
	}

	void assignNum(int src)
	{
		static int counter = 0;

		vDFSTree[src].invested = true;
		vDFSTree[src].v = src;
		vDFSTree[src].num = counter++;
		for ( vector<int >::iterator it=vGraph[src].begin(); it!=vGraph[src].end(); ++it )
		{
			if ( !vDFSTree[*it].invested )
			{
				vDFSTree[*it].v_parent = src;
				assignNum( *it );
			}
		}
	}

	void assignLow(int src)
	{
		vDFSTree[src].low = vDFSTree[src].num;
		for ( vector<int >::iterator it=vGraph[src].begin(); it!=vGraph[src].end(); ++it )
		{
			if ( vDFSTree[*it].num>vDFSTree[src].num ) //forward
			{
				assignLow(*it);
				if ( vDFSTree[*it].low>=vDFSTree[src].num && vDFSTree[src].num!=0 )
					mArticulationPoint.insert(std::make_pair(*it, *it));
				vDFSTree[src].low = min( vDFSTree[src].low, vDFSTree[*it].low);
			}
			else//backward
			{
				if ( vDFSTree[src].v_parent!=*it )
					vDFSTree[src].low = min(vDFSTree[src].low, vDFSTree[*it].num);
			}
		}
	}

	void PrintGraph(void)
	{
		int i(0);
		cout << "graph: " << endl;
		for ( vector<vector<int> >::iterator itvv=vGraph.begin(); itvv!=vGraph.end(); ++itvv )
		{
			cout << i++ << ": ";
			for ( vector<int >::iterator itv=itvv->begin(); itv!=itvv->end(); ++itv )
				cout << *itv << " ";
			cout << endl;
		}
	}
	void PrintDFSTree(void)
	{
		cout << "dfstree: "<< endl;
		int i(0);
		for ( i=0; i<iTreeSize; ++i )
			cout << i << ": " << vDFSTree[i].num << " "<< vDFSTree[i].low << endl;

		cout << "dfstree generation: "<< endl;
		for ( i=0; i<iTreeSize; ++i )
			cout << vDFSTree[i].v_parent << "-->" << vDFSTree[i].v << endl;
	}
	void PrintArti(void)
	{
		cout << "articulation point: " << endl;
		for ( map<int, int>::iterator it=mArticulationPoint.begin(); it!=mArticulationPoint.end(); ++it)
		{
			cout << it->second << " " ;
		}
		cout << endl;
	}
	void PrintAll(void)
	{
		PrintGraph();
		PrintDFSTree();
		PrintArti();
	}

	void Dfst_Ex( int src)
	{
		InitTree();
		assignNum(src);
		assignLow(src);
		PrintAll();
	}
};

#include <iostream>
#include <cstdlib>
#include <vector>
#include "dfs.h"

#define _DFST_EX_

int main()
{
#ifdef _DFST_
	{
		using namespace dfst;

		vector<int> v;
		vGraph.clear();

		//v0
		v.clear();
		v.push_back(1);
		v.push_back(3);
		v.push_back(4);
		vGraph.push_back(v);
		//v1
		v.clear();
		v.push_back(0);
		v.push_back(2);
		v.push_back(3);
		vGraph.push_back(v);
		//v2
		v.clear();
		v.push_back(1);
		v.push_back(3);
		v.push_back(4);
		vGraph.push_back(v);

		//v3
		v.clear();
		v.push_back(0);
		v.push_back(1);
		v.push_back(2);
		vGraph.push_back(v);

		//v4
		v.clear();
		v.push_back(0);
		v.push_back(2);
		v.push_back(3);
		vGraph.push_back(v);

		InitTree();
		dfs(1);
		PrintAll();
	}
#endif

#ifdef _DFST_EX_
	{
		using namespace dfst_ex;

		vector<int> v;
		vGraph.clear();

		//v0
		v.clear();
		v.push_back(1);
		v.push_back(3);
		vGraph.push_back(v);
		//v1
		v.clear();
		v.push_back(0);
		v.push_back(2);
		vGraph.push_back(v);
		//v2
		v.clear();
		v.push_back(1);
		v.push_back(3);
		v.push_back(6);
		vGraph.push_back(v);

		//v3
		v.clear();
		v.push_back(0);
		v.push_back(2);
		v.push_back(4);
		v.push_back(5);
		vGraph.push_back(v);

		//v4
		v.clear();
		v.push_back(3);
		v.push_back(5);
		vGraph.push_back(v);

		//v5
		v.clear();
		v.push_back(3);
		v.push_back(4);
		vGraph.push_back(v);

		//v6
		v.clear();
		v.push_back(2);
		vGraph.push_back(v);

		Dfst_Ex(0);
	}
#endif

	system("pause");
	return 0;
}