广度优先搜索遍历连通图

//广度优先搜索遍历连通图
#include <iostream>
using namespace std;

#define MVNum 100
#define MAXQSIZE 100

typedef char VerTexType;
typedef int ArcType;
bool visited[MVNum];

typedef struct {
	VerTexType vexs[MVNum];
		ArcType arcs[MVNum][MVNum];
	int vexnum, arcnum;
}Graph;

typedef struct {
	ArcType* base;
	int front;
	int rear;
}sqQueue;

void InitQueue(sqQueue& Q) {
	Q.base = new ArcType[MAXQSIZE];
	if (!Q.base)
		exit(1);
	Q.front = Q.rear = 0;
}

void EnQueue(sqQueue& Q, ArcType e) {
	if ((Q.rear + 1) % MAXQSIZE == Q.front)
		return;
	Q.base[Q.rear] = e;
	Q.rear = (Q.rear + 1) % MAXQSIZE;
}

bool QueueEmpty(sqQueue Q) {
	if (Q.rear == Q.front)
		return true;
	return false;
}

void Dequeue(sqQueue& Q, ArcType& u) {
	u = Q.base[Q.front];
	Q.front = (Q.front + 1) % MAXQSIZE;
}

int LocateVex(Graph G, VerTexType v) {
	for (int i = 0;i < G.vexnum;++i)
		if (G.vexs[i] == v)
			return i;
	return -1;
}

void CreateUDN(Graph& G) {
	int i, j, k;
	cout << "请输入总顶点数，总边数，以空格隔开:";
	cin >> G.vexnum >> G.arcnum;
	cout << endl;
	cout << "输入点的名称，如a" << endl;
	for (i = 0;i < G.vexnum;++i) {
		cout << "请输入第" << (i + 1) << "个点的名称:";
		cin >> G.vexs[i];
	}
	cout << endl;
	for (i = 0;i < G.vexnum;++i) {
		for (j = 0;j < G.vexnum;++i)
			G.arcs[i][j] = 0;
	}
	cout << "输入边依附的顶点，如a b" << endl;
	for (k = 0;k < G.vexnum;k++) {
		VerTexType v1, v2;
		cout << "请输入第" << (k + 1) << "条边依附的顶点:";
		cin >> v1 >> v2;
		i = LocateVex(G, v1);
		j = LocateVex(G, v2);
		G.arcs[i][j] = 1;
		G.arcs[j][i] = G.arcs[i][j];
	}
}

int FirstAdjVex(Graph G, int v) {
	int i;
	for (i = 0;i < G.vexnum;++i) {
		if (G.arcs[v][i] == 1 && visited[i] == false)
			return i;
	}
	return -1;
}

int NextAdjVex(Graph G, int u, int w) {
	int i;
	for (i = w;i < G.vexnum;++i) {
		if (G.arcs[u][i] == 1 && visited[i] == false)
			return i;
	}
	return -1;
}

void BFS(Graph G, int v) {
	sqQueue Q;
	ArcType u;
	ArcType w;

	cout << G.vexs[v] << "  ";
	visited[v] = true;
	InitQueue(Q);
	EnQueue(Q, v);
	while (!QueueEmpty(Q)) {
		Dequeue(Q, u);
		for (w = FirstAdjVex(G, u);w >= 0;w = NextAdjVex(G, u, w)) {
			if (!visited[w]) {
				cout << G.vexs[w] << "   ";
				visited[w] = true;
				EnQueue(Q, w);
			}
		}
	}
}

int main() {
	cout << "广度优先搜索遍历连通图";
	Graph G;
	CreateUDN(G);
	cout << endl;
	cout << "无向连通图G创建完成！" << endl;

	cout << "请输入遍历连通图的起始点：";
	VerTexType c;
	cin >> c;

	int i;
	for (i = 0;i < G.vexnum;++i) {
		if (c == G.vexs[i])
			break;
	}
	cout << endl;
	while (i >= G.vexnum) {
		cout << "该点不存在，请重新输入！" << endl;
		cout << "请输入遍历连通图的起始点：";
		cin >> c;
		for (i = 0;i < G.vexnum;++i) {
			if (c == G.vexs[i])
				break;
		}
	}
	cout << "广度优先搜索遍历连通图结果：" << endl;
	BFS(G, i);

	cout << endl;
	return 0;
}