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[Data structures]Depth first search forest

2019-7-23 萧 写技术

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

#define MAX 20
#define INFINIT	65535

typedef struct _ArcCell{
	int adj; // Weight or flag about connection
	int *info; // Other information
}ArcCell;

typedef char VertexType;

typedef enum{
	DG,
	DN,
	UDG,
	UDN
}GraphKind;

typedef struct _MGraph{
	VertexType vexs[MAX];
	ArcCell arcs[MAX][MAX];
	int vexnum;
	int arcnum;
	GraphKind kind;
}MGraph;

typedef struct _TreeNode{
	char data;
	struct _TreeNode *left;
	struct _TreeNode *right;
}TreeNode;

int visited[MAX];

int LocateVex(MGraph *G, VertexType v)
{
	int i=0;
	while(i<G->vexnum && G->vexs[i] != v){
		i++;
	}
	if(i<G->vexnum){
		return i;
	}else{
		return -1;
	}
}

int CreateUDG(MGraph *G)
{
	int i,j,k;
	char v1,v2;

	scanf(" %d %d", &G->vexnum, &G->arcnum);	
	for(i=0; i<G->vexnum; i++){
		scanf(" %c", &G->vexs[i] );
	}
	for(i=0; i<G->vexnum; i++){
		for(j=0; j<G->vexnum; j++){
			G->arcs[i][j].adj = INFINIT;
		}
	}
	for(k=0; k<G->arcnum; k++){
		scanf(" %c %c", &v1, &v2);
		i=LocateVex(G, v1);
		j=LocateVex(G, v2);	
		G->arcs[i][j].adj = 1;
		G->arcs[j][i].adj = 1;	
	}
	return 1;
}

int FirstAdjvex(MGraph *G, int v)
{
	int i=0;
	while(i<G->vexnum && G->arcs[v][i].adj == INFINIT){
		i++;
	}	
	if(i<G->vexnum){
		return i;
	}else{
		return -1;
	}
}

int NextAdjvex(MGraph *G, int v, int w)
{
	int i=w+1;
	while(i<G->vexnum && G->arcs[v][i].adj == INFINIT){
		i++;
	}
	if(i<G->vexnum){
		return i;
	}else{
		return -1;
	}

}

void DFSTree(MGraph *G, int v, TreeNode *T)
{
	int w;
	int first = 1;
	TreeNode *p = NULL;
	TreeNode *q = NULL;

	visited[v] = 1;
	for(w = FirstAdjvex(G, v); w>=0; w = NextAdjvex(G, v, w) ){
		if(!visited[w]){
			p = (TreeNode *)malloc(sizeof(TreeNode));
			p->data = G->vexs[w];
			p->left = p->right = NULL;	

			if(first){
				first = 0;
				T->left = p; //Child
			}else{
				q->right = p; //Sibling
			}
			
			q = p;

			DFSTree(G, w, q);
		}
	}
}	

void DFSForest(MGraph *G, TreeNode **T)
{
	int i;
	int first = 1;
	TreeNode *p = NULL;
	TreeNode *q = NULL;

	for(i=0; i<G->vexnum; i++){
		visited[i] = 0;
	}
	for(i=0; i<G->vexnum; i++){
		if(!visited[i]){
			p = (TreeNode *)malloc(sizeof(TreeNode));
			p->data = G->vexs[i];
			p->left = p->right = NULL;

			if(first){
				*T = p;
			}else{
				q->right = p;
			}
			q = p;

			DFSTree(G, i, q);
		}
	}
}

void PrintTree(TreeNode *T)
{
	if(T != NULL){
		printf(" %c(", T->data);
		PrintTree(T->left);
		printf(" , ");
		PrintTree(T->right);
		printf(") ");
	}	
}

void main()
{
	MGraph G;	
	TreeNode *T;

	printf("log.anycle.com\n\n");
	printf("Create graph:\n");
	CreateUDG(&G);
	printf("\n");

	printf("Depth first search travers:\n");
	DFSForest(&G, &T);
	printf("Depth first search travers creation tree:\n");
	PrintTree(T);
	printf("\n");
}

标签: Data Structures data_structures