(转载)图的深度优先遍历非递归算法

纠结图的深度优先搜索算法好久，非递归算法需要用到栈来记录上一次访问的结果，但是大脑中反应不出来。这里做一个记录：

栈的用处：在这一步执行完成之后，下一步需要用到上一步执行的结果，用栈来实现往往是最有效的。

以下是转载的内容：

深度优先遍历算法的非递归实现需要了解深度优先遍历的执行过程，设计一个栈来模拟递归实现中系统设置的工作栈，算法的伪代码描述为：

假设图采用邻接矩阵作为存储结构，具体算法如下：

　深度优先遍历算法的非递归实现需要了解深度优先遍历的执行过程，设计一个栈来模拟递归实现中系统设置的工作栈，算法的伪代码描述为：


　　假设图采用邻接矩阵作为存储结构，具体算法如下：


<PRE class=cpp name="code">#include<iostream>
#include <queue>
using namespace std;
#define  MAX_NODE 12
bool visited[MAX_NODE] ;
int stack[ MAX_NODE] ;
queue<int> q;
int Matric[MAX_NODE][MAX_NODE] =
{
    {-1,1,1,0,0,0,0,0,0,0,0,0},
    {1,-1,1,0,1,1,0,0,0,0,0,0},
    {1,1,-1,1,0,0,0,0,0,0,0,0},
    {0,0,1,-1,1,0,0,0,0,0,1,1},
    {0,1,0,1,-1,0,0,0,0,0,0,0},
    {0,1,0,0,0,-1,0,0,0,0,1,0},
    {0,0,0,0,0,0,-1,1,1,1,0,0},
    {0,0,0,0,0,0,1,-1,0,0,0,0},
    {0,0,0,0,0,0,1,0,-1,1,1,0},
    {0,0,0,0,0,0,1,0,1,-1,0,1},
    {0,0,0,1,0,1,0,0,1,0,-1,0},
    {0,0,0,1,0,0,0,0,0,1,0,-1},
};
void DFS( int v)
{
    cout << " v"<< v ;
    int top = -1 ;
    visited[v] = true ;
    stack[++top] = v ;
    while ( top != -1)
    {
        v = stack[top] ;
        for (int i = 0 ; i < MAX_NODE ; i++)
        {
            if (Matric[v][i] == 1 &&!visited[i])
            {
                cout << " v" << i ;
                visited[i] = true ;
                stack[ ++top ] = i ;
                break ;
            }
        }
        if( i == MAX_NODE)
        {
            top -- ;
        }
    }

}


void BFS( int v)
{
    int node = 0;
    q.push(v);
    visited[v] = true;
    while( !q.empty())
    {
        node = q.front();
        for ( int i = 0; i < MAX_NODE; i++ )
        {
            if ( Matric[node][i] == 1 && !visited[i])
            {
                visited[i] = true;
                q.push(i);
            }
        }
        cout <<" v" << node;
        q.pop();
    }


}
void Init()
{

    int i = 0;
    for ( i = 0; i < MAX_NODE; i++)
    {
        visited[i] = false;
    }
}
int main()
{
    Init();
    DFS( 1 ) ;
    cout << endl ;
    Init();
    BFS( 1 );
    cout << endl;
    Init();
    DFS( 6 );
    cout <<endl;
    return 0 ;
}</PRE>
<PRE></PRE>
<PRE class=cpp name="code"></PRE>

　深度优先遍历算法的非递归实现需要了解深度优先遍历的执行过程，设计一个栈来模拟递归实现中系统设置的工作栈，算法的伪代码描述为： 


　　假设图采用邻接矩阵作为存储结构，具体算法如下：

#include<iostream>
#include <queue>
using namespace std;
#define  MAX_NODE 12
bool visited[MAX_NODE] ;
int stack[ MAX_NODE] ;
queue<int> q;
int Matric[MAX_NODE][MAX_NODE] =
{
    {-1,1,1,0,0,0,0,0,0,0,0,0},
    {1,-1,1,0,1,1,0,0,0,0,0,0},
    {1,1,-1,1,0,0,0,0,0,0,0,0},
    {0,0,1,-1,1,0,0,0,0,0,1,1},
    {0,1,0,1,-1,0,0,0,0,0,0,0},
    {0,1,0,0,0,-1,0,0,0,0,1,0},
    {0,0,0,0,0,0,-1,1,1,1,0,0},
    {0,0,0,0,0,0,1,-1,0,0,0,0},
    {0,0,0,0,0,0,1,0,-1,1,1,0},
    {0,0,0,0,0,0,1,0,1,-1,0,1},
    {0,0,0,1,0,1,0,0,1,0,-1,0},
    {0,0,0,1,0,0,0,0,0,1,0,-1},
};
void DFS( int v)
{
    cout << " v"<< v ;
    int top = -1 ;
    visited[v] = true ;
    stack[++top] = v ;
    while ( top != -1)
    {
        v = stack[top] ;
        for (int i = 0 ; i < MAX_NODE ; i++)
        {
            if (Matric[v][i] == 1 &&!visited[i])
            {
                cout << " v" << i ;
                visited[i] = true ;
                stack[ ++top ] = i ;
                break ;
            }
        }
        if( i == MAX_NODE)
        {
            top -- ;
        }
    }

}


void BFS( int v)
{
    int node = 0;
    q.push(v);
    visited[v] = true;
    while( !q.empty())
    {
        node = q.front();
        for ( int i = 0; i < MAX_NODE; i++ )
        {
            if ( Matric[node][i] == 1 && !visited[i])
            {
                visited[i] = true;
                q.push(i);
            }
        }
        cout <<" v" << node;
        q.pop();
    }


}
void Init()
{

    int i = 0;
    for ( i = 0; i < MAX_NODE; i++)
    {
        visited[i] = false;
    }
}
int main()
{
    Init();
    DFS( 1 ) ;
    cout << endl ;
    Init();
    BFS( 1 );
    cout << endl;
    Init();
    DFS( 6 );
    cout <<endl;
    return 0 ;
}