Question

您好我正在进行深度优先搜索的项目，程序使用每个相邻顶点的链表并使用堆栈。该程序有两个结构Vertex Struct，它有两个字段，一个是链表，指针和一个名为visted的布尔变量标记为false。第二个结构是一个Graph，它有两个字段，一个Vertex Struct数组和一个顶点数的整数。我遇到的问题是，当调用深度优先搜索功能时，即使堆栈为空，它也永远不会停止，深度优先功能会打印每个被访问的顶点。有人可以帮我找到一种方法让程序停止堆栈是空的;

#include <iostream>
#include "linklist.h"
#include "Stack.h"
using namespace std;

typedef int vertexNum;
Stack S;

struct Vertex
{
    List p;
    bool visted;
    Vertex()
    {
       p = NULL;
       visted = false;
    }
};

struct Graph
{
   int numVert;
   Vertex* vertArr;

   Graph(int num)
   {
       numVert = num;
       vertArr = new Vertex[numVert+1];
   }
};

void readGraph(Graph& G)
{
    cout << "Enter adjacent vertices, enter 0 to stop" << endl;
    vertexNum v1, v2;
    cin >> v1;
    while (v1 != 0)
    {
        cin >> v2;
        insertTail(v2,G.vertArr[v1].p);
        insertTail(v1,G.vertArr[v2].p);
        //G.vertArr[v1].p = cons(v2,G.vertArr[v1].p);
        //G.vertArr[v2].p = cons(v1,G.vertArr[v2].p);
        cin >> v1;
    }
}

void printGraph(Graph& G)
{
    for (int i = 1; i <= G.numVert; i++)
    {
       cout << "Vertex "<< i << " Adjacent list ";
       printList(G.vertArr[i].p);
    }
}

void DFS(int x,Graph& G)
{

        push(x,S);
        printList(S.p);
        G.vertArr[x].visted = true;
        if (!G.vertArr[head(G.vertArr[x].p)].visted)
        {
            DFS(head(G.vertArr[x].p),G);
        }
        else
        {
            cout << ""<< endl;
            List temp = tail(G.vertArr[x].p);
            if(isEmpty(temp))
            {
                pop(S);
                G.vertArr[peek(S)].visted = false;
                DFS(pop(S),G);
            }
            else if(!G.vertArr[head(temp)].visted)
            {
                DFS(head(temp),G);
            }
            else
            {
               int num =0;
               for (List pp = temp; !isEmpty(pp); pp = tail(pp))
               {
                   if(!G.vertArr[head(pp)].visted)
                   {
                       num = head(pp);
                       break;
                   }
               }
               if (num == 0)
               {
                   pop(S);
                   G.vertArr[peek(S)].visted = false;
                   DFS(pop(S),G);
               }
               else
                   DFS(num,G);
           }
       }  


}
int main()
{
    int x,y;
    cout << "Enter the number of vertices" << endl;
    cin >> x;
    Graph p(x);
    readGraph(p);
    printGraph(p);
    cout << "\nEnter start vertex" << endl;
    cin >> y;
    DFS(y,p);
}

程序输出

Enter the number of vertices
13
Enter adjacent vertices, enter 0 to stop
1 4
1 5
1 2
1 3
2 7
2 8
8 13
8 7
11 12
10 9
13 12
9 6
6 5
0
Vertex 1 Adjacent list 4 5 2 3 
Vertex 2 Adjacent list 1 7 8 
Vertex 3 Adjacent list 1 
Vertex 4 Adjacent list 1 
Vertex 5 Adjacent list 1 6 
Vertex 6 Adjacent list 9 5 
Vertex 7 Adjacent list 2 8 
Vertex 8 Adjacent list 2 13 7 
Vertex 9 Adjacent list 10 6 
Vertex 10 Adjacent list 9 
Vertex 11 Adjacent list 12 
Vertex 12 Adjacent list 11 13 
Vertex 13 Adjacent list 8 12 

Enter start vertex
5

5 
1 5 
4 1 5 

1 5 

2 1 5 

7 2 1 5 

8 7 2 1 5 

13 8 7 2 1 5 

12 13 8 7 2 1 5 
11 12 13 8 7 2 1 5 

12 13 8 7 2 1 5 

13 8 7 2 1 5 

8 7 2 1 5 

7 2 1 5 

2 1 5 

1 5 

3 1 5 

1 5 

5 

6 5 
9 6 5 
10 9 6 5 

9 6 5 

6 5 

5

这是堆栈和链接列表h文件

#ifndef LINKLIST_H_
#define LINKLIST_H_

#include <cstdlib>
#include <iostream>
using namespace std;

struct listCell
{
    int head;
    listCell* tail;

    listCell(int h, listCell* t)
    {
        head =h;
        tail = t;
    }
};

typedef listCell* List;
typedef const listCell* constList;

List emptyList = NULL;

int head(List L)
{
   return L->head;
}

List tail(List L)
{
   return L->tail;
}

bool isEmpty(List L)
{
   return L == emptyList;
}

List cons(int h, List t)
{
   return new listCell(h,t);
}

int listLength(List L)
{

    if (isEmpty(L))
    {
       return 0;
    }
    else
    {
        return 1 + listLength(tail(L));
    }
}


void printList(List L)
{
    List k = L;
    while (!isEmpty(k))
    {
        int val = head(k);
        k = k->tail;
        cout << val << " ";
    }
    cout << "\n";
}

这是堆栈文件

#ifndef STACK_H_
#define STACK_H_
#include "linklist.h"

struct Stack
{
   List p;

   Stack()
   {
       p = NULL;
   }
};

void push(int x, Stack& list)
{
    list.p =cons(x,list.p);
}

int peek(Stack& list)
{
   return head(list.p);
}

int pop(Stack& list)
{
   return delHead(list.p);
}

bool isEmpty(Stack& list)
{
   return isEmpty(list.p);
}

int size(Stack& list)
{
   return listLength(list.p);
}



#endif /* STACK_H_ */

深度优先搜索c ++

0 个答案: