数据结构-图基础-dfs、bfs的非递归写法

bfs（宽度优先搜索）利用队列

void BFS(Graph G, int num)  //num为从该点开始进行搜索
{
    queue<int>Queue;
    cout << num <<" ";   
    visit[num] = 1;
    Queue.push(num);  //访问完该点后入队列
    while (!Queue.empty())  //队列不为空时
    {
        num = Queue.front();  //出队
        Queue.pop();
        for (int i = 0; i < G.n; i++)
        {
            if (G.edge[num][i] != 0 && visit[i] == 0)   //找到与之相连的顶点入队
            {
                cout << i << " ";
                Queue.push(i);
                visit[i] = 1;
            }
        }
    }
    cout << endl;
}

dfs（深度优先搜索）利用栈

void DFS2(Graph G, int num) //深度优先搜索非递归算法
{
    stack<int> Stack;
    visit[num] = 1;
    Stack.push(num);
    while (!Stack.empty())
    {
        num = Stack.top();
        Stack.pop();
        cout << num << " ";
        for (int i = G.n - 1; i >= 0; i--)
        {
            if (G.edge[num][i] != 0 && visit[i] == 0)
            {
                Stack.push(i);
                visit[i] = 1;
            }
        }
    }
    cout << endl;
}

最后附上原文代码和链接。

#include<iostream>
#include<fstream>
#include<queue>
#include<stack>
using namespace std;
#define MAX 10
typedef struct graph
{
    int n;   //顶点数
    int e;  //边数
    int edge[MAX][MAX];  //标识边，0为没有该边，不为0则有边，且标识边的权值
}Graph;
int visit[MAX] = { 0 };    //表示该顶点有没有访问过，没有为0，有为1
 
void InitGraph(Graph *G)
{
    for (int i = 0; i < MAX;i++)
    for (int j = 0; j < MAX; j++)
        (*G).edge[i][j] = 0;
}
 
//广度优先搜索算法
void BFS(Graph G, int num)  //num为从该点开始进行搜索
{
    queue<int>Queue;
    cout << num <<" ";   
    visit[num] = 1;
    Queue.push(num);  //访问完该点后入队列
    while (!Queue.empty())  //队列不为空时
    {
        num = Queue.front();  //出队
        Queue.pop();
        for (int i = 0; i < G.n; i++)
        {
            if (G.edge[num][i] != 0 && visit[i] == 0)   //找到与之相连的顶点入队
            {
                cout << i << " ";
                Queue.push(i);
                visit[i] = 1;
            }
        }
    }
    cout << endl;
}
 
void DFS1(Graph G, int num) //深度优先搜索递归算法
{
    int i;
    cout << num << " ";
    visit[num] = 1;
    for (i = 0; i < G.n; i++)
    {
        if (G.edge[num][i] != 0 && visit[i] == 0)
            DFS1(G, i);
    }
}
void DFS2(Graph G, int num) //深度优先搜索非递归算法
{
    stack<int> Stack;
    visit[num] = 1;
    Stack.push(num);
    while (!Stack.empty())
    {
        num = Stack.top();
        Stack.pop();
        cout << num << " ";
        for (int i = G.n - 1; i >= 0; i--)
        {
            if (G.edge[num][i] != 0 && visit[i] == 0)
            {
                Stack.push(i);
                visit[i] = 1;
            }
        }
    }
    cout << endl;
}
int main()
{
    int a, b, v, i;
    Graph G;
    ifstream cin("data.txt");
    cin >> G.n >> G.e;   //n,e为顶点个数，边个数
    InitGraph(&G);   //对G进行初始化，整个MAX范围初始化
    for (i = 0; i < G.e; i++)   //建图
    {
        cin >> a >> b >> v;  //a,b为顶点，v为权值
        G.edge[a][b] = v;
        G.edge[b][a] = v;
    }
    BFS(G, 0); //0为开始搜索的顶点序号
    for (i = 0; i < MAX; i++)
        visit[i] = 0;
    DFS1(G, 0);
    cout << endl;
    for (i = 0; i < MAX; i++)
        visit[i] = 0;
    DFS2(G, 0);
    system("pause");
    return 0;
}
————————————————
版权声明：本文为CSDN博主「遥遥远远」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/u011392877/article/details/50932403