DFS--深度優先搜索--圖的鄰接表表示

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

# define ok 1
# define NULL 0
# define MAX 20			//最大頂點數 

typedef struct ARCNODE
{
	int adjvex;			//該邊所指的頂點的位置 
	struct ARCNODE * next;		//指向下一條邊的指針 
//  int weight;			//有向圖邊的權	
}arcnode,* node;		//表的節點 

typedef struct VNODE
{
	char data;		//頂點信息 
	node firstarc;		//指向第一條依附該頂點的邊的弧指針
}vnode,adjlist[MAX];	//頭結點 

typedef struct algraph
{
	adjlist vertices;
	int visited[MAX];		//訪問標誌數組 
	int vexnum,arcnum;		//圖的當前頂點數和弧度 
}mgraph;

void init_mgraph(mgraph &g) 		//初始化圖 
{
	memset(g.visited,0,sizeof(int)*MAX);		//訪問標誌數字置0，表示沒有被訪問 
//	for (int i=0;i<MAX;++i)
//	g.visited[i] = 0;
	g.vexnum = 0;
	g.arcnum = 0;
}

int locatevex(mgraph &g,char v)			//查找頂點v在頂點向量中的位置 
{
	int i;
	for (i=0; v!=g.vertices[i].data && i<g.vexnum; ++i)
	;
	if (i>=g.vexnum)
	return -1;
	return i;
}

void add_vex(mgraph &g)			//增加節點 
{
	printf ("請輸入無向圖的頂點數\n");
	scanf ("%d",&g.vexnum);
	printf ("輸入頂點信息：\n");
	for (int i=0;i<g.vexnum;++i)
	{
		scanf (" %c",&g.vertices[i].data);		//構造頂點向量 
		g.vertices[i].firstarc = NULL;
	}
}

void add_arc(mgraph &g)			//增加邊 
{
	node s,t;
	printf ("請輸入無向圖的邊數\n");
	scanf ("%d",&g.arcnum);
	char ch1,ch2;
	printf ("輸入信息\n");
	for (int k=0; k<g.arcnum; ++k)
	{
		scanf (" %c %c",&ch1,&ch2);
		int i = locatevex(g,ch1);
		int j = locatevex(g,ch2);		//確定v1，v2在g中的位置 
		s = (node)malloc(sizeof(arcnode));
		t = (node)malloc(sizeof(arcnode));
		
		s->adjvex = j;				//該邊所指向的頂點的位置爲j 
		s->next = g.vertices[i].firstarc;
		g.vertices[i].firstarc = s;
		
		t->adjvex = i;		//該邊所指向的頂點的位置爲i； 
		t->next = g.vertices[j].firstarc;
		g.vertices[j].firstarc = t;
	}
}

void creat_mgraph(mgraph &g)		//構造鄰接鏈表 
{
	add_vex(g);			//增加節點 
	add_arc(g);			//增加邊 
}

void printadjlist(mgraph &g)
{
	int i;
	node p;
	printf ("編號    頂點    鄰點編號\n");
	for (i=0;i<g.vexnum;++i)
	{
		printf ("  %d       %c      ",i,g.vertices[i].data);
		for (p=g.vertices[i].firstarc;p;p=p->next)
		printf ("%d  ",p->adjvex);
		printf ("\n");
	}
}

void visit(mgraph &g,int i)
{
	printf ("%c ",g.vertices[i].data);
	g.visited[i] = 1;
}

void DFStraverse(mgraph &g,int i)		//深度優化搜索 
{										//從第i個頂點開始搜索 
	visit(g,i);
	node p;
	for ((p=g.vertices[i].firstarc); p ;(p=p->next))
	if (!g.visited[p->adjvex])
	DFStraverse(g,p->adjvex);
}

int main(void)
{
	mgraph g;
	init_mgraph(g);
	creat_mgraph(g);
	printadjlist(g);
	DFStraverse(g,0);
	
	return 0;
}