[图] 2 遍历-DFS|BFS-递归与非递归

版权声明：本文为博主原创文章，若有错误之处望大家批评指正！转载需附上原文链接，谢谢！ https://blog.csdn.net/summer_dew/article/details/82999993

邻接表

// DFS
int visit[MAX_VERTEX_NUM];
void DFSUtil_AL(ALGraph G, int v) {
	ArcNode *p;
	visit[v]=1;
	Visit(G.vers[v].data);
	for (p=G.vers[v].firstarc; p; p=p->next)
		if (!visit[p->adjV])
			DFSUtil_AL(G, p->adjV);
}
void DFS_AL(ALGraph G) {
	int i;
	for (i=0; i<MAX_VERTEX_NUM; i++) {
		visit[MAX_VERTEX_NUM] = 0;
	}
	for (i=0; i<G.vernum; ++i) {
		if (!visit[i])
			DFSUtil_AL(G, i);
	}
}
// DFS非递归
void DFSTraverse_Nonrecurisve(ALGraph G) {
	int visit[maxSize];
	int i,j;
	ArcNode *p;
	int stack[maxSize],top=-1;	
	for (i=0; i<maxSize; i++) visit[i]=0;

	for (i=0; i<G.vernum; i++) {
		if (visit[i]==0) { //没有访问过
			//从它开始
			top=-1; //清空栈
			stack[++top]=i; //入栈
			visit[i]=1; Visit(G.vers[i].data); //访问
			while (top!=-1) { //栈不空
				j = stack[top]; //得出栈顶
				//从j开始走
				for (p=G.vers[j].firstarc; p; p=p->next) {
					if (!visit[p->adjV]) { //这条边没有访问过
						visit[p->adjV]=1;Visit(G.vers[p->adjV].data); //访问
						stack[++top]=p->adjV; //从这个点继续
						break;
					} else //这条边走过了，找下条边 
						continue;
				}
				if (p==NULL) { //j的邻边走完了，返回上个结点，继续往下走
					--top;
				}
			}
		}
	}
}
// BFS
void BFSUntil_AL(ALGraph G,int v) {
	ArcNode *p;
	int i;
	int queue[maxSize],front,rear;
	front=rear=0;

	queue[rear]=v; rear=(rear+1)%maxSize; //入队列
	while (front!=rear) { //队列未满
		i=queue[front]; front=(front+1)%maxSize; //出队列
		//访问i
		visit[i]=1;
		Visit(G.vers[i].data);
		//访问i的邻边
		for (p=G.vers[i].firstarc; p; p=p->next) {
			if (visit[p->adjV]==0) {
				queue[rear]=p->adjV;
				rear=(front+1)%maxSize;
			}
		}
	}
}
void BFS_AL(ALGraph G) { //BFS遍历
	int i;
	for (i=0; i<MAX_VERTEX_NUM; ++i) visit[i]=0; //初始化

	for (i=0; i<G.vernum; i++) {
		if (visit[i]==0) {//没有访问过
			BFSUntil_AL(G, i);
		}
	}
}

完整代码

【邻接表】

#include<stdio.h>
#include<stdlib.h>

#ifndef BASE
#define BASE
#define TRUE 1
#define FALSE 0
#define OK 1
#define ERROR 0
#define INFEASIBLE -1
#define OVERFLOW -2
typedef int Status;
typedef int bool;
#endif

#define VertexType char //点类型
#define VRType int //边类型
#define maxSize 20
void Visit(VertexType e) {
	printf("%c", e);
}

#define MAX_VERTEX_NUM 20
typedef enum{DG, UDG} GraphKind;
typedef struct ArcNode{
	int adjV; //边指向的顶点
	VRType weight; //权重
	struct ArcNode *next;
}ArcNode; //边
typedef struct VNode{
	VertexType data;
	ArcNode *firstarc;
}VNode, AdjList[MAX_VERTEX_NUM]; //顶点
typedef struct{
	GraphKind kind;
	int vernum,arcnum;
	AdjList vers; 
}ALGraph;


/*------------------------
 |7.14 创建有向图的邻接表|
 ------------------------*/
Status InitGraph_AL(ALGraph *pG) { //初始化
	int i;
	pG->arcnum = 0;
	pG->vernum = 0;
	for (i=0; i<MAX_VERTEX_NUM; ++i)
		pG->vers[i].firstarc = NULL; //VC++6.0中指针初始化为0xcccccccc
	return OK;
}
int LocateVex_AL(ALGraph G, VertexType e) { //定位值为e的元素下标
	int i;
	for (i=0; i<G.vernum; ++i) {
		if (G.vers[i].data == e) {
			return i;
		}
	}
	return -1;
}
Status CreateDG_AL(ALGraph *pG) { //创建有向图的邻接表
	//输入规则：顶点数目->弧的数目->各顶点的信息->各条弧的信息
	int i,a,b;
	char tmp[MAX_VERTEX_NUM];
	char h,t;
	ArcNode *p, *q;

	InitGraph_AL(pG); //VC++6.0中指针初始化为0xcccccccc，如果不将指针初始化为NULL，会出错
	//图的类型
	pG->kind = DG;
	//顶点数目
	scanf("%d", &i); if (i<0) return ERROR;
	pG->vernum = i;
	//弧的数目
	scanf("%d", &i); if (i<0) return ERROR;
	pG->arcnum = i;
	//各顶点信息
	scanf("%s", tmp);
	for (i=0; i<pG->vernum; ++i) pG->vers[i].data=tmp[i];
	//弧的信息
	for (i=0; i<pG->arcnum; ++i) {
		scanf("%s", tmp);
		h = tmp[0]; t = tmp[2];
		a = LocateVex_AL(*pG, h);
		b = LocateVex_AL(*pG, t);
		if (a<0 || b<0) return ERROR;
		p = (ArcNode *)malloc(sizeof(ArcNode)); if (!p) exit(OVERFLOW);
		p->adjV=b;p->next=NULL;
		if (pG->vers[a].firstarc) { //已经有边了
			for (q = pG->vers[a].firstarc; q->next; q=q->next) ; //找到最后一条
			q->next = p;
		} else { //第一条边
			pG->vers[a].firstarc = p;
		}
	}
	return OK;
}

// DFS
int visit[MAX_VERTEX_NUM];
void DFSUtil_AL(ALGraph G, int v) {
	ArcNode *p;
	visit[v]=1;
	Visit(G.vers[v].data);
	for (p=G.vers[v].firstarc; p; p=p->next)
		if (!visit[p->adjV])
			DFSUtil_AL(G, p->adjV);
}
void DFS_AL(ALGraph G) {
	int i;
	for (i=0; i<MAX_VERTEX_NUM; i++) {
		visit[MAX_VERTEX_NUM] = 0;
	}
	for (i=0; i<G.vernum; ++i) {
		if (!visit[i])
			DFSUtil_AL(G, i);
	}
}
// DFS非递归
void DFSTraverse_Nonrecurisve(ALGraph G) {
	int visit[maxSize];
	int i,j;
	ArcNode *p;
	int stack[maxSize],top=-1;	
	for (i=0; i<maxSize; i++) visit[i]=0;

	for (i=0; i<G.vernum; i++) {
		if (visit[i]==0) { //没有访问过
			//从它开始
			top=-1; //清空栈
			stack[++top]=i; //入栈
			visit[i]=1; Visit(G.vers[i].data); //访问
			while (top!=-1) { //栈不空
				j = stack[top]; //得出栈顶
				//从j开始走
				for (p=G.vers[j].firstarc; p; p=p->next) {
					if (!visit[p->adjV]) { //这条边没有访问过
						visit[p->adjV]=1;Visit(G.vers[p->adjV].data); //访问
						stack[++top]=p->adjV; //从这个点继续
						break;
					} else //这条边走过了，找下条边 
						continue;
				}
				if (p==NULL) { //j的邻边走完了，返回上个结点，继续往下走
					--top;
				}
			}
		}
	}
}
// BFS
void BFSUntil_AL(ALGraph G,int v) {
	ArcNode *p;
	int i;
	int queue[maxSize],front,rear;
	front=rear=0;

	queue[rear]=v; rear=(rear+1)%maxSize; //入队列
	while (front!=rear) { //队列未满
		i=queue[front]; front=(front+1)%maxSize; //出队列
		//访问i
		visit[i]=1;
		Visit(G.vers[i].data);
		//访问i的邻边
		for (p=G.vers[i].firstarc; p; p=p->next) {
			if (visit[p->adjV]==0) {
				queue[rear]=p->adjV;
				rear=(front+1)%maxSize;
			}
		}
	}
}
void BFS_AL(ALGraph G) { //BFS遍历
	int i;
	for (i=0; i<MAX_VERTEX_NUM; ++i) visit[i]=0; //初始化

	for (i=0; i<G.vernum; i++) {
		if (visit[i]==0) {//没有访问过
			BFSUntil_AL(G, i);
		}
	}
}

int main() {
/*
6
11
ABCDEF
B,A
B,D
C,B
C,F
D,C
D,E
D,F
E,A
F,A
F,B
F,E
*/
	ALGraph G;

	CreateDG_AL(&G); 
	
	DFS_AL(G);printf("\n");
	DFSTraverse_Nonrecurisve(G);printf("\n");
	BFS_AL(G);printf("\n");

	return 0;
}