深度优先遍历

#include<stdio.h>
#include<stdlib.h>
#define MAX_VER_NUM 20

//DG有向图  UDG无向图
typedef enum { DG, UDG }GraphKind;

typedef struct ArcNode
{
	int adjvex;  //节点数值
	struct ArcNode* next;  //指向邻接节点的指针
}ArcNode;

typedef struct VertexNode
{
	char vexdata;   //节点的数值
	ArcNode* head;  //头指针
}VertexNode;

typedef struct
{
	VertexNode vertex[MAX_VER_NUM];
	int vexnum, arcnum;
	GraphKind Type;
}LGraph;

//索引vex位置并返回
int index(char vex, LGraph* lg)
{
	int i;
	for (i = 1;i <= lg->vexnum;i++)
	{
		if (lg->vertex[i].vexdata == vex)
		{
			return i;
		}
	}
	return 0;
}

void Creat_LG(LGraph* lg)
{
	int i, j, v1_index, v2_index, type;
	char v1, v2;
	ArcNode* p1, * p2;
	printf("please input graph type 0.DG 1.UDG. input nums:");
	scanf_s("%d", &type);
	if (type == 0)
	{
		lg->Type = DG;
	}
	else if (type == 1)
	{
		lg->Type = UDG;
	}
	else
	{
		printf("please input 0 or 1!!!");
		return;
	}
	printf("Please input vexnum:");
	//顶点数
	scanf_s("%d", &lg->vexnum);
	printf("Please input arcnum:");
	//弧数
	scanf_s("%d", &lg->arcnum);
	getchar();
	for (i = 1;i <= lg->vexnum;i++)
	{
		lg->vertex[i].head = NULL;
		printf("Please input %d vex:", i);
		scanf_s("%c", &lg->vertex[i].vexdata,1);
		getchar();
	}
	for (j = 1;j <= lg->arcnum;j++)
	{
		printf("Please input %d arc(vex1 vex2):", j);
		scanf_s("%c %c", &v1,1,&v2,1);
		getchar();
		v1_index = index(v1, lg);
		v2_index = index(v2, lg);
		if (lg->Type == 1)
		{
			p1 = (ArcNode*)malloc(sizeof(ArcNode));
			p1->adjvex = v2_index;
			//前插
			p1->next = lg->vertex[v1_index].head;
			lg->vertex[v1_index].head = p1;

			p2 = (ArcNode*)malloc(sizeof(ArcNode));
			p2->adjvex = v1_index;
			//前插
			p2->next = lg->vertex[v2_index].head;
			lg->vertex[v2_index].head = p2;
		}
		else
		{
			p1 = (ArcNode*)malloc(sizeof(ArcNode));
			p1->adjvex = v2_index;
			p1->next = lg->vertex[v1_index].head;
			lg->vertex[v1_index].head = p1;
		}

	}
}

void Print_LG(LGraph* lg)
{
	int i;
	ArcNode* p;
	if (lg->Type == 0)
		printf("Is Direct Graph\n");
	else
		printf("Is UNDirect Graph\n");
	for (i = 1;i <= lg->vexnum;i++)
	{
		printf("%c", lg->vertex[i].vexdata);
		p = lg->vertex[i].head;
		while (p)
		{
			printf("->%c", lg->vertex[p->adjvex].vexdata);
			p = p->next;
		}
		printf("\n");
	}
}

//深度优先遍历递归
int visit1[MAX_VER_NUM];

void visit(LGraph* lg, int v)
{
	printf("%c", lg->vertex[v].vexdata);
}

void DFS1(LGraph* lg, int v0)
{
	ArcNode* p;
	visit1[v0] = 1;
	visit(lg, v0);
	p = lg->vertex[v0].head;
	while (p)
	{
		if (!visit1[p->adjvex])
			DFS1(lg, p->adjvex);
		p = p->next;
	}
}

void DFS1Traverse(LGraph* lg)
{
	int v;
	for (v = 1;v <= lg->vexnum;v++)
		visit1[v] = 0;
	for (v = 1; v <= lg->vexnum; v++)
	{
		if (!visit1[v])
			DFS1(lg, v);
	}
}


//图的深度优先遍历非递归  数组栈 
void DFS2(LGraph* lg, int v0)
{
	int stack[MAX_VER_NUM];
	ArcNode* p;
	int visit[MAX_VER_NUM] = { 0 }, top = -1, k = 0;
	p = lg->vertex[v0].head;
	stack[++top] = v0;
	visit[v0] = 1;
	printf("%c", lg->vertex[v0].vexdata);
	while (top != -1)
	{
		
		
		while (p != NULL &&visit[p->adjvex] != 1)
		{  //将该顶点的所有邻边元素进栈
			stack[++top] = p->adjvex;
			p = p->next;
		}
		k = stack[top--];  //取栈顶元素	
		p = lg->vertex[k].head;   //指向该顶点的第一条边
		//如果到最后一个都已经返问则出栈，去上一个栈元素
		if (p == NULL && lg->vertex[k].head != NULL)
		{
			--top; //出栈
		}
		else 
		{
			if (lg->vertex[k].head != NULL && !visit[k])
			{
				printf("%c", lg->vertex[k].vexdata);
				visit[k] = 1;
				stack[++top] = p->adjvex; //在进栈
			}
			else
			{
				if (!visit[k])
				{
					printf("%c", lg->vertex[k].vexdata);
					visit[k] = 1;
				}
			}
			
		}
		
	}
}
int main()
{
	LGraph LG;
	Creat_LG(&LG);
	Print_LG(&LG);
	printf("DFS1:");
	DFS1Traverse(&LG);
	printf("\n");
	printf("DFS2:");
	DFS2(&LG, 1);
	printf("\n");
	return 0;
}