图的遍历之广度优先搜索和深度优先搜索

#include<iostream>
#include<stack>
#include<queue>
#define MAX_VERTS 20
using namespace std;
class Vertex//顶点
{
public:
//char Label;
Vertex(char lab)
{
Label = lab;
wasVisited = false;
}
public:
bool wasVisited;
char Label;//顶点字符
};
class Graph//图
{
public:
Graph();
~Graph();
void addVertex(char lab);//增加一个顶点
void addEdge(int start, int end);//增加一条边
void printMatrix();//打印矩阵
void showVertex(int v);
void DFS();//深度优先搜索
void BFS();

private:
Vertex* vertexList[MAX_VERTS];//指针数组
int nVerts;//实际中顶点的个数
int adjMat[MAX_VERTS][MAX_VERTS];//做邻接矩阵的数组
int getAdjUnvisitedVertex(int v);//邻接的未访问的顶点
};
void Graph::DFS()
{
stack<int>gStack;//保存的堆栈的下标
vertexList[0]->wasVisited = true;//从第一个顶点开始
showVertex(0);
gStack.push(0);//把访问过的压入堆栈
int v;
while (gStack.size() > 0)//当堆栈为空是结束
{
v = getAdjUnvisitedVertex(gStack.top());//v是顶点下标
if (v == -1)
gStack.pop();//向回反
else
{
vertexList[v]->wasVisited = true;
showVertex(v);
gStack.push(v);
}
}
cout << endl;
for (int j = 0; j < nVerts; j++)
vertexList[j]->wasVisited = false;
}
void Graph::BFS()
{
queue<int >gQueue;
vertexList[0]->wasVisited = true;//从第一个下标开始
showVertex(0);
gQueue.push(0);//访问过的每一个顶点都要放入队列
int vert1, vert2;
while (gQueue.size()>0)//如果队列中有顶点
{
vert1 = gQueue.front();//把A拿出来
gQueue.pop();//把A删除掉
vert2 = getAdjUnvisitedVertex(vert1);//找与A相邻接的
while (vert2 != -1)//找出所有与A相邻接的
{
vertexList[vert2]->wasVisited = true;//标记为访问过
showVertex(vert2);//显示
gQueue.push(vert2);//放入队列
vert2 = getAdjUnvisitedVertex(vert1);

}

}
cout << endl;
for (int j = 0; j < nVerts;j++)
vertexList[j]->wasVisited = false;
}
int Graph::getAdjUnvisitedVertex(int v)
{
for (int j = 0; j < nVerts; j++)
{
if ((adjMat[v][j] == 1) && (vertexList[j]->wasVisited == false))
return j;
}
return -1;
}
void Graph::showVertex(int v)
{
cout << vertexList[v]->Label << " ";

}
Graph::Graph()
{
nVerts = 0;
for (int i = 0; i < MAX_VERTS; i++)
for (int j = 0; j < MAX_VERTS; j++)
adjMat[i][j] = 0;
}
void Graph::addVertex(char lab)
{
vertexList[nVerts++] = new Vertex(lab);
}
void Graph::addEdge(int start, int end)
{
adjMat[start][end] = 1;
adjMat[end][start] = 1;
}
void Graph::printMatrix()
{
for (int i = 0; i < nVerts; i++)
{
for (int j = 0; j < nVerts; j++)
cout << adjMat[i][j] << " ";
cout << endl;
}
}
Graph::~Graph()
{
for (int i = 0; i < nVerts; i++)
delete vertexList[i];
}
int main()
{

Graph g;
g.addVertex('A');//0
g.addVertex('B');//1
g.addVertex('C');//2
g.addVertex('D');//3
g.addVertex('E');//4

g.addEdge(0, 1);//A_B
g.addEdge(0, 3);//A-D
g.addEdge(1, 0);//B-A
g.addEdge(1, 4);//B-E
g.addEdge(2, 4);//C-E
g.addEdge(3, 0);//C-A
g.addEdge(3, 4);//C-D
g.addEdge(4, 1);//E-B
g.addEdge(4, 2);//E-C
g.addEdge(4, 3);//E-D
g.printMatrix();
cout << "深度优先搜索的结果：" << endl;
g.DFS();
cout << "广度优先搜索的结果：" << endl;
g.BFS();

system("pause");
return 0;
}