图的遍历之广度优先搜索

最新推荐文章于 2025-12-18 17:00:31 发布

转载最新推荐文章于 2025-12-18 17:00:31 发布 · 1.5k 阅读

文章标签：

#struct #算法 #input #null #存储

转载区专栏收录该内容

6 篇文章

订阅专栏

本文介绍了一个使用C++实现的图的广度优先遍历(BFS)算法。该算法采用邻接表来存储图，并通过队列辅助完成遍历过程。文章详细展示了如何创建图结构、输入顶点及边，以及进行广度优先遍历的过程。

#include <iostream>
#include <algorithm>
#include <iterator>
#include <queue>

using namespace std;    

#define MAX_VERTEX_NUM 10

struct Node
{
	int adjvex;
	struct Node *next;
	int info;
};

typedef struct VNode
{
	char data;
	Node *first;
}VNode, AdjList[MAX_VERTEX_NUM];

struct Graph 
{
	AdjList vertices;
	int vexnum, arcnum;
};

int visited[MAX_VERTEX_NUM];

int locateVex(Graph G, char u)
{
	int i;
	for (i = 0; i < G.vexnum; i++)
	{
		if (u == G.vertices[i].data)
			return i;
	}

	if (i == G.vexnum)
	{
		printf("Error u!\n");
		exit(1);
	}

	return 0;
}

void createGraph(Graph &G)
{
	int i, j, k, w;
	char v1, v2, enter;

	Node *p;
	printf("input vexnum & arcnum:\n");
	scanf("%d", &G.vexnum);
	scanf("%d", &G.arcnum);
	printf("input vertices:\n");
	for (i = 0; i < G.vexnum; i++)
	{
		scanf("%c%c", &enter, &G.vertices[i].data);
		G.vertices[i].first = NULL;
	}

	printf("input Arcs(v1, v2, w):\n");
	for (k = 0; k < G.arcnum; k++)
	{
		scanf("%c%c", &enter, &v1);
		scanf("%c%c", &enter, &v2);
		scanf("%d", &w);
		i = locateVex(G, v1);
		j = locateVex(G, v2);
		p = (Node *)malloc(sizeof(Node));
		p->adjvex = j;
		p->info = w;
		p->next = G.vertices[i].first;
		G.vertices[i].first = p;
	}
}

void BFSTraverse(Graph &G)

{

	queue<int> Q;

	for(int v = 0; v < G.vexnum; ++v)
		visited[v] = false;

	for(int v = 0;v < G.vexnum; ++v)
	{
		if(!visited[v])
		{
			Q.push(v);
			while(!Q.empty())
			{
				int u = Q.front();
				Q.pop();
				visited[u]=true;
				printf("->%c",G.vertices[u].data);//visit一下
				for(Node *w= G.vertices[u].first; w ; w = w->next)
					if(!visited[w->adjvex])
						Q.push(w->adjvex);
			}//while
		}//if
	}

}//BFSTraverse

int main()
{
	Graph G;
	createGraph(G);
	BFSTraverse(G);
}