图论 - 图的深度优先遍历c++实现

图的深度优先遍历c++实现

• 深度优先搜索

---

邻接矩阵的创建

	int i, j, m, a, b;
	cin >> n >> m;
	//初始化二维矩阵
	for (i = 1; i <= n; i++)
		for (j = 1; j <= n; j++)
			if (i == j)e[i][j] = 0;
			else e[i][j] = 0x3f;

	//读入顶点之间的边
	for (i = 1; i <= m; i++)
	{
		cin >> a >> b;
		e[a][b] = 1;
		e[b][a] = 1; //无向图需要将其对应的点的左边也赋值为1
	}

---

深度优先搜索算法实现

void dfs(int cur)
{
	int i;
	cout << cur << " ";
	sum++;//每访问一个节点sum就++
	if (sum == n)return;//所有的顶点已经访问过直接退出
	for (int i = 1; i <= n; i++)
	{
		//判断当前顶点cur到顶点i是否有边,并判断顶点i是否已经访问过
		if (e[cur][i] == 1 && book[i] == 0)
		{
			book[i] = 1;
			dfs(i);
		}
	}
	return;
}

---

整体代码

#include <iostream>
#include <cstdio>
using namespace std;
int book[101], sum, n, e[101][101];

void dfs(int cur)
{
	int i;
	cout << cur << " ";
	sum++;//没访问一个节点sum就++
	if (sum == n)return;//所有的顶点已经访问过直接退出
	for (int i = 1; i <= n; i++)
	{
		//判断当前顶点cur到顶点i是否有边,并判断顶点i是否已经访问过
		if (e[cur][i] == 1 && book[i] == 0)
		{
			book[i] = 1;
			dfs(i);
		}
	}
	return;
}
int main()
{
	int i, j, m, a, b;
	cin >> n >> m;
	//初始化二维矩阵
	for (i = 1; i <= n; i++)
		for (j = 1; j <= n; j++)
			if (i == j)e[i][j] = 0;
			else e[i][j] = 0x3f;

	//读入顶点之间的边
	for (i = 1; i <= m; i++)
	{
		cin >> a >> b;
		e[a][b] = 1;
		e[b][a] = 1; //无向图需要将其对应的点的左边也赋值为1
	}

	//从顶点1出发
	book[1] = 1;//标记一号顶点已经被访问
	dfs(1);//从1号顶点开始遍历
	system("pause");
	return 0;
}