【原创】递归函数实现迷宫问题

 

//迷宫问题
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#define mazefile "maze.txt"

using namespace std;
class Escape
{
public:
       int left;
       int forward;
       int right;
       friend ostream& operator<<(ostream& out,Escape& e);
       bool operator!();
};
ostream& operator<<(ostream& out,Escape& e) //重载<<
{
       if(e.left!=0) out <<e.left <<"号路口 ";
       if(e.forward!=0) out <<e.forward <<"号路口 ";
       if(e.right!=0) out <<e.right <<"号路口 ";
       return out;
}
bool Escape::operator!() //重载!
{
    if(this->left==0 && this->forward==0 && this->right==0)
         return false;
    return true;
}
vector<Escape> ev;
vector<int> vi;
int _EXIT;
int ston(const string& s);
bool findex(int escape);
int main(int argc,char* argv[])
{

      string line;
      ifstream in(mazefile);
      Escape esc;
      int i=0;
      while(getline(in,line))
      {
          int l=0;
          string s;
          l=line.find(":");
          s=line.substr(0,l);
          line=line.substr(l+1);  //获取冒号后的字符串
          l=line.find(",");
          esc.left=ston(line.substr(0,l));  //取得第一个逗号前的数字
          line=line.substr(l+1);
          l=line.find(",");
          esc.forward=ston(line.substr(0,l));//取得第二个逗号前的数字
          line=line.substr(l+1);
          esc.right=ston(line);              //取得第三个逗号前的数字
          ev.push_back(esc);
          if(!ev[i])
               cout <<i <<"号路口通向：" <<ev[i] <<endl;
          else
               cout <<i <<"号路口是死路！" <<endl;
          i++;
      }
      cout <<"请输入您要到达的路口：";
      cin >>_EXIT;
      if(findex(1))
           cout <<"1号路口->";
           for(int i=vi.size()-1;i>=0;i--)
                cout <<vi[i] <<"号路口->";

      cout <<"EXIT" <<endl;
      system("pause");
      return 0;
}

bool findex(int escape)  //递归查找
{
     if(escape>0)
     {
          if(escape==_EXIT) return true;
          if(findex(ev[escape].left))
          {
                 vi.push_back(ev[escape].left);
                 return true;
          }
          if(findex(ev[escape].forward))
          {
                 vi.push_back(ev[escape].forward);
                 return true;
          }
          if(findex(ev[escape].right))
          {
                 vi.push_back(ev[escape].right);
                 return true;
          }
     }
     return false;
}

int ston(const string& s)  //将字符串转换为整数并返回
{
    const char* c=s.c_str();
    int num=0;
    while(*c)
         num=num*10+(int)((*c++)-'0');
    return num;
}

 

maze.txt的内容如下

0:0,0,0
1:2,0,0
2:4,0,0
3:0,0,0
4:3,5,0
5:6,0,0
6:7,0,0
7:8,9,0
8:0,0,18
9:10,0,0
10:11,13,0
11:12,0,14
12:0,0,0
13:16,0,0
14:15,20,0
15:17,0,0
16:21,0,0
17:0,19,0
18:22,0,0
19:0,0,0
20:0,23,0
21:0,0,23
22:0,0,0
23:0,0,24
24:26,25,27
25:0,27,0
26:28,0,0
27:0,0,27
28:0,0,0