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 ;
- }