有关路径搜索的一个算法

由各个直线组成的路网，求一点到另一点的所有路径：

FindRateWay.h文件代码如下：

#include <list>
#include <vector>
#include <stack>
#include "GELNSG3D.h"

typedef std::vector<AcGeLineSeg3d> vecLineSeg;

//死胡同点记录
struct DeadList
{
 AcGePoint3d ptOri; //参照点
 AcGePoint3dArray ptDeadAry; //死胡同点（即从参照点出发的不能走的下一点）
};
typedef std::vector<DeadList> vecDeadPt;

class CFindRateWay 
{
public:
 CFindRateWay(std::list<AcGeLineSeg3d>& lstRate,AcGePoint3d ptStart,AcGePoint3d ptEnd);
 virtual ~CFindRateWay();

 //寻找所有路径（排除回路），没找到返回FALSE
 BOOL FindWay(std::vector<vecLineSeg>& vecWay);

private:
 //检查路径点是否可继续向下走，如果可走则返回TRUE并返回一个可走的邻接点ptNext
 BOOL IsValid(AcGePoint3d pt, std::stack<AcGePoint3d>& staRatePt,std::vector<vecLineSeg>& vecWay, IN vecDeadPt& vecDead, OUT AcGePoint3d& ptNext);

 //查找某点的所有邻接点
 void FindPtNear(AcGePoint3d pt,AcGePoint3dArray& PtAry);

 //从栈中寻找指定点，找到返回TRUE
 BOOL FindPtFromStack(AcGePoint3d pt, IN std::stack<AcGePoint3d>& staPt);

 //通过栈中轨迹记录到路径组中
 void SaveRate(std::stack<AcGePoint3d>& staPt,std::vector<vecLineSeg>& vecWay);

 //通过两点从m_lstRate中获得AcGeLineSeg3d
 BOOL FindLineSegFromList(AcGePoint3d pt1, AcGePoint3d pt2, AcGeLineSeg3d& Line);

 //将栈中点记录到点数组中
 void SaveStaPt2PtAry(std::stack<AcGePoint3d>& staPt,AcGePoint3dArray& ptAry);

 //判断从起点到pt整个路径是否已经属于成功路径结果的一部分，条件：pt不在栈中
 BOOL IsPartOfSuccRate(AcGePoint3d pt, std::stack<AcGePoint3d>& staRatePt, std::vector<vecLineSeg>& vecWay);

 //判断一个点pt1是否为另一个点pt2的死胡同点
 BOOL IsDeadPt(AcGePoint3d pt1, AcGePoint3d pt2,IN vecDeadPt& vecDead);

 std::list<AcGeLineSeg3d> m_lstRate;
 AcGePoint3d m_ptStart; //出发点
 AcGePoint3d m_ptEnd; //目的点

};

------------------------------------------------------------

FindRateWay.cpp文件代码如下：

// FindRateWay.cpp: implementation of the CFindRateWay class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "resource.h"
#include "FindRateWay.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CFindRateWay::CFindRateWay(std::list<AcGeLineSeg3d>& lstRate,AcGePoint3d ptStart,AcGePoint3d ptEnd)
{
 m_lstRate = lstRate;
 m_ptStart = ptStart;
 m_ptEnd = ptEnd;
}

CFindRateWay::~CFindRateWay()
{

}

//寻找所有路径（排除回路），没找到返回FALSE
BOOL CFindRateWay::FindWay(std::vector<vecLineSeg>& vecWay)
{
 //排除出发点和目标点相同的情况
 if (m_ptStart.isEqualTo(m_ptEnd))
  return FALSE;

 //从起点出发
 AcGePoint3d ptCur = m_ptStart;
 vecDeadPt vecDead;
 std::stack<AcGePoint3d> staPt;
 do
 {
  if (ptCur.isEqualTo(m_ptEnd))
  {
   //找到一条通路，记下所有路径
   SaveRate(staPt, vecWay);
   //清除死胡同点组
   vecDead.clear();
   //回退当前点
   ptCur = staPt.top();
   staPt.pop();
  }
  AcGePoint3d ptNext;
  if (IsValid(ptCur,staPt,vecWay,vecDead,ptNext))
  {
   staPt.push(ptCur);
   ptCur = ptNext;
  }
  else
  {
   //当前点不能继续往下走，回退
   if (staPt.empty())
    break;
   //记录死胡同的点
   if (!ptCur.isEqualTo(m_ptEnd))
   {
    if (!IsPartOfSuccRate(ptCur,staPt,vecWay))
    {
     DeadList clsDead;
     clsDead.ptOri = staPt.top();
     clsDead.ptDeadAry.append(ptCur);
     vecDead.push_back(clsDead);
    }
   }
   ptCur = staPt.top();
   staPt.pop();
  }
 } while(!staPt.empty());
 return (vecWay.size() == 0)?FALSE:TRUE;
}

//将栈中点记录到点数组中
void CFindRateWay::SaveStaPt2PtAry(std::stack<AcGePoint3d>& staPt,AcGePoint3dArray& ptAry)
{
 std::stack<AcGePoint3d> staPt2; //临时记录栈中元素
 while (!staPt.empty())
 {
  AcGePoint3d ptTop = staPt.top();
  ptAry.append(ptTop);
  staPt2.push(ptTop);
  staPt.pop();
 }
 ptAry.reverse();
 //恢复栈
 while (!staPt2.empty())
 {
  staPt.push(staPt2.top());
  staPt2.pop();
 }
}

//通过栈中轨迹记录到路径组中
void CFindRateWay::SaveRate(std::stack<AcGePoint3d>& staPt,
       std::vector<vecLineSeg>& vecWay)
{
 AcGePoint3dArray ptAry;
 SaveStaPt2PtAry(staPt, ptAry);

 vecLineSeg vecRate;
 for (int i=0; i<ptAry.logicalLength()-1; i++)
 {
  AcGeLineSeg3d line;
  if (FindLineSegFromList(ptAry[i], ptAry[i+1], line))
   vecRate.push_back(line);
 }
 AcGePoint3d ptStart = staPt.top();
 AcGePoint3d ptEnd = m_ptEnd;
 AcGeLineSeg3d EndLine(ptStart, ptEnd);
 vecRate.push_back(EndLine);
 vecWay.push_back(vecRate); //找到一条路径，加入
}

//通过两点从m_lstRate中获得AcGeLineSeg3d
BOOL CFindRateWay::FindLineSegFromList(AcGePoint3d pt1, AcGePoint3d pt2, AcGeLineSeg3d& Line)
{
 std::list<AcGeLineSeg3d>::iterator iter;
 for (iter=m_lstRate.begin(); iter!=m_lstRate.end(); iter++)
 {
  AcGeLineSeg3d line = *iter;
  if (line.isOn(pt1) && line.isOn(pt2))
  {
   Line = line;
   return TRUE;
  }
 }
 return FALSE;
}

//检查路径点是否可继续向下走，如果可走则返回TRUE并返回一个可走的邻接点ptNext
BOOL CFindRateWay::IsValid(AcGePoint3d pt, std::stack<AcGePoint3d>& staRatePt,
         std::vector<vecLineSeg>& vecWay,IN vecDeadPt& vecDead,
         OUT AcGePoint3d& ptNext)
{
 //找到邻接点
 AcGePoint3dArray ptNearAry;
 FindPtNear(pt, ptNearAry);
 if (ptNearAry.logicalLength() == 0)
  return FALSE;
 //将当前判断点加入到栈中
 staRatePt.push(pt);
 for (int i=0; i<ptNearAry.logicalLength(); i++)
 {
  //在栈中存在这个邻接点则代表不能继续向下走
  if (FindPtFromStack(ptNearAry[i], staRatePt))
   continue;
  //判断从起点到ptNearAry[i]整个路径是否已经属于成功路径结果的一部分
  if (IsPartOfSuccRate(ptNearAry[i],staRatePt,vecWay))
   continue;
  //属于死胡同点找下一个
  if (IsDeadPt(ptNearAry[i], pt, vecDead))
   continue;
  ptNext = ptNearAry[i];
  staRatePt.pop();
  return TRUE;
 }
 staRatePt.pop();
 return FALSE;
}

//判断一个点pt1是否为另一个点pt2的死胡同点
BOOL CFindRateWay::IsDeadPt(AcGePoint3d pt1, AcGePoint3d pt2,IN vecDeadPt& vecDead)
{
 vecDeadPt::iterator iter;
 for (iter=vecDead.begin(); iter!=vecDead.end(); iter++)
 {
  DeadList clsDead = *iter;
  if (clsDead.ptOri.isEqualTo(pt2))
  {
   for (int i = 0; i<clsDead.ptDeadAry.logicalLength(); i++)
   {
    if (clsDead.ptDeadAry[i].isEqualTo(pt1))
    {
     return TRUE;
    }
   }
  }
 }
 return FALSE;
}

//判断从起点到pt整个路径是否已经属于成功路径结果的一部分，条件：pt不在栈中
BOOL CFindRateWay::IsPartOfSuccRate(AcGePoint3d pt, std::stack<AcGePoint3d>& staRatePt,
         std::vector<vecLineSeg>& vecWay)
{
 AcGePoint3dArray ptAry;
 SaveStaPt2PtAry(staRatePt,ptAry);
 ptAry.append(pt);

 int iCount = ptAry.logicalLength();
 std::vector<vecLineSeg>::iterator iter;
 for (iter=vecWay.begin();iter!=vecWay.end();iter++)
 {
  vecLineSeg vec = *iter;
  int i=0;
  BOOL bNoPart = FALSE;
  for (; i<vec.size(); i++)
  {
   AcGeLineSeg3d line = vec.at(i);
   if (i>=ptAry.logicalLength()-1)
    return TRUE;
   if (line.isOn(ptAry[i]) && line.isOn(ptAry[i+1]))
    continue;
   bNoPart = TRUE;
   break; //不是成功路径的一部分，循环下一条
  }
  if (!bNoPart)
   return TRUE;
 }
 return FALSE;
}

//查找某点的所有邻接点
void CFindRateWay::FindPtNear(AcGePoint3d pt,AcGePoint3dArray& PtAry)
{
 std::list<AcGeLineSeg3d>::iterator iter;
 for (iter=m_lstRate.begin(); iter!=m_lstRate.end(); iter++)
 {
  AcGeLineSeg3d line = *iter;
  if (line.isOn(pt) == Adesk::kTrue)
  {
   AcGePoint3d ptStart = line.startPoint();
   AcGePoint3d ptEnd = line.endPoint();
   int iFind = -1;
   if (!PtAry.find(ptStart,iFind) && !pt.isEqualTo(ptStart))
    PtAry.append(ptStart);
   if (!PtAry.find(ptEnd,iFind) && !pt.isEqualTo(ptEnd))
    PtAry.append(ptEnd);
  }
 }
}

//从栈中寻找指定点，找到返回TRUE
BOOL CFindRateWay::FindPtFromStack(AcGePoint3d pt, IN std::stack<AcGePoint3d>& staPt)
{
 std::stack<AcGePoint3d> staPt2; //用来临时存放栈元素
 BOOL bFind = FALSE;
 while (!staPt.empty())
 {
  AcGePoint3d ptItem = staPt.top();
  if (ptItem.isEqualTo(pt))
  {
   bFind = TRUE;
   break;
  }
  staPt2.push(ptItem);
  staPt.pop();
 }
 //将staPt2中元素依次压回
 while (!staPt2.empty())
 {
  staPt.push(staPt2.top());
  staPt2.pop();
 }

 return bFind;
}

---------------------------------

调用方式：

// This is command 'DEMOCMD'
//命令用来构建道路各段，
void ARXDemoDemoCmd()
{
 // TODO: Implement the command
 std::list<AcGeLineSeg3d> lstRate;
 AcGeLineSeg3d line1(AcGePoint3d(300,0,0),AcGePoint3d(300,100,0));
 lstRate.push_back(line1);
 
 AcGeLineSeg3d line2(AcGePoint3d(100,100,0),AcGePoint3d(100,500,0));
 lstRate.push_back(line2);
 
 AcGeLineSeg3d line3(AcGePoint3d(100,100,0),AcGePoint3d(300,100,0));
 lstRate.push_back(line3);
 
 AcGeLineSeg3d line4(AcGePoint3d(0,500,0),AcGePoint3d(100,500,0));
 lstRate.push_back(line4);
 
 AcGeLineSeg3d line5(AcGePoint3d(100,500,0),AcGePoint3d(200,500,0));
 lstRate.push_back(line5);
 
 AcGeLineSeg3d line6(AcGePoint3d(200,400,0),AcGePoint3d(200,500,0));
 lstRate.push_back(line6);
 
 AcGeLineSeg3d line7(AcGePoint3d(200,500,0),AcGePoint3d(400,500,0));
 lstRate.push_back(line7);
 
 AcGeLineSeg3d line8(AcGePoint3d(200,400,0),AcGePoint3d(400,400,0));
 lstRate.push_back(line8);
 
 AcGeLineSeg3d line9(AcGePoint3d(200,300,0),AcGePoint3d(200,400,0));
 lstRate.push_back(line9);
 
 AcGeLineSeg3d line10(AcGePoint3d(200,200,0),AcGePoint3d(200,300,0));
 lstRate.push_back(line10);
 
 AcGeLineSeg3d line11(AcGePoint3d(200,300,0),AcGePoint3d(400,300,0));
 lstRate.push_back(line11);
 
 AcGeLineSeg3d line12(AcGePoint3d(200,200,0),AcGePoint3d(400,200,0));
 lstRate.push_back(line12);
 
 AcGeLineSeg3d line13(AcGePoint3d(400,200,0),AcGePoint3d(400,300,0));
 lstRate.push_back(line13);
 
 AcGeLineSeg3d line14(AcGePoint3d(400,300,0),AcGePoint3d(400,400,0));
 lstRate.push_back(line14);
 
 AcGeLineSeg3d line15(AcGePoint3d(400,400,0),AcGePoint3d(400,500,0));
 lstRate.push_back(line15);

 AcGeLineSeg3d line16(AcGePoint3d(400,500,0),AcGePoint3d(600,500,0));
 lstRate.push_back(line16);

 AcGeLineSeg3d line17(AcGePoint3d(400,400,0),AcGePoint3d(600,400,0));
 lstRate.push_back(line17);

 AcGeLineSeg3d line18(AcGePoint3d(400,300,0),AcGePoint3d(600,300,0));
 lstRate.push_back(line18);

 AcGeLineSeg3d line19(AcGePoint3d(400,200,0),AcGePoint3d(600,200,0));
 lstRate.push_back(line19);

 AcGeLineSeg3d line20(AcGePoint3d(600,400,0),AcGePoint3d(600,500,0));
 lstRate.push_back(line20);

 AcGeLineSeg3d line21(AcGePoint3d(600,300,0),AcGePoint3d(600,400,0));
 lstRate.push_back(line21);

 AcGeLineSeg3d line22(AcGePoint3d(600,200,0),AcGePoint3d(600,300,0));
 lstRate.push_back(line22);

 AcGeLineSeg3d line23(AcGePoint3d(600,100,0),AcGePoint3d(600,200,0));
 lstRate.push_back(line23);

 AcGeLineSeg3d line24(AcGePoint3d(600,100,0),AcGePoint3d(700,100,0));
 lstRate.push_back(line24);

 AcGeLineSeg3d line25(AcGePoint3d(600,500,0),AcGePoint3d(700,500,0));
 lstRate.push_back(line25);

 AcGeLineSeg3d line26(AcGePoint3d(300,100,0),AcGePoint3d(500,100,0));
 lstRate.push_back(line26);

 AddAllRacePt();

 //按lst创建实体
 g_ObjIdAry.setLogicalLength(0);
 CreateLineEnt(g_ObjIdAry, lstRate);
 
 //调用搜索类查找所有路径
 CDlgSetRacePos dlg;
 if (dlg.DoModal() == IDOK)
 {
  AcGePoint3d ptStart = g_pt[dlg.m_iStartPtIndex];
  AcGePoint3d ptEnd = g_pt[dlg.m_iEndPtIndex];
  CFindRateWay clsFindRate(lstRate,ptStart, ptEnd);
  g_vecRateWay.clear();
  clsFindRate.FindWay(g_vecRateWay); 
  acutPrintf(_T("/n总共%d条路"), g_vecRateWay.size());

  ShowRace();
 }
}

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/lhscad/archive/2010/02/20/5313536.aspx