数据结构----邻接矩阵-邻接表

要表示一个图G=(V,E)，有两种标准的表示方法，即邻接表和邻接矩阵。这两种表示法既可用于有向图，也可用于无向图。通常采用邻接表表示法，因为用这种方法表示稀疏图（图中边数远小于点个数）比较紧凑。但当遇到稠密图（|E|接近于|V|^2）或必须很快判别两个给定顶点手否存在连接边时，
通常采用邻接矩阵表示法，例如求最短路径算法中，就采用邻接矩阵表示。

#include<stdio.h>
#include<string.h>
#include <stdlib.h> 
#define MAXN 50


//邻接矩阵
int edge[MAXN][MAXN];
int other(){
	int i,j;
	int n,m;
	int u,v;
	int od,id;
	while(1){
		scanf("%d%d",&n,&m);
		if(n==0 && m==0){
			printf("没有输入边和点的个数\n");
			break;
		}
		memset(edge, 0, sizeof(edge)); 
		for(i=0;i<m;i++){
			scanf("%d%d",&u,&v);
			edge[u-1][v-1] = 1;
		} 
		for(i=0;i<n;i++){
			od = 0;
			for(j=0;j<n;j++){
				od += edge[i][j];
			}
			if(i==0){
				printf("%d",od);
			}
			else{
				printf(" %d",od);
			}
		}
		printf("\n");
		for(i=0;i<n;i++){
			id =0;
			for(j=0;j<n;j++){
				id += edge[j][i];
			}
			if(i==0){
				printf("%d",id);
			}
			else{
				printf(" %d",id);
			}
		}
		printf("\n");
		}
	return 0;
}



//邻接表
typedef struct arcnode * arc;

typedef struct vnode * vno;

typedef struct lgraph * lgr;
struct arcnode{
	int id;
	arc  next_arcnode;
};

struct vnode{
	int id;
	arc inhead;
	arc outhead;
};

struct lgraph{
	struct vnode vnodes[MAXN];
	int vex=0;
	int arc=0;
};

lgr create_null_lg(){
	
}







lgr create_lg(lgr lg){
	int i;
	int n,m;
	arc p=NULL;
	for(i=0;i<lg->vex;i++){
		lg->vnodes[i].inhead = lg->vnodes[i].outhead = NULL;
	}
	for(i=0;i<lg->arc;i++){
		scanf("%d%d",&n,&m);
		n--;
		m--;
		p = (arc)malloc(sizeof(struct arcnode));
		p->id = m;
		p->next_arcnode = lg->vnodes[n].inhead;
		lg->vnodes[n].inhead = p;
		p = (arc)malloc(sizeof(struct arcnode));
		p->id = n;
		p->next_arcnode = lg->vnodes[m].outhead;
		lg->vnodes[m].outhead = p;
	}
	return lg;
}


void free_lg(lgr lg){
	int i;
	arc p;
	for(i=0;i<lg->vex;i++){
		p = lg->vnodes[i].inhead;
		while(p!=NULL){
			lg->vnodes[i].inhead = p->next_arcnode;    
			free(p);
			p = lg->vnodes[i].inhead; 	
		}
		p = lg->vnodes[i].outhead;
		while(p!=NULL){
			lg->vnodes[i].outhead = p->next_arcnode;    
			free(p);
			p = lg->vnodes[i].outhead; 	
		}
	}
}




int main(){
	int i;
	int m,n;
	int id,od;
	arc p;
	struct lgraph lg;
	while(1){
		printf("输入多少条边和点"); 
		scanf("%d%d",&(lg.vex),&(lg.arc));
		if(lg.vex==0){
			break;
		}
		create_lg(&lg);
		for(i=0;i<lg.vex;i++){
			od =0;
			p = lg.vnodes[i].inhead;
			while(p!=NULL){
				od ++;
				p = p->next_arcnode;
			}
			if(i==0){
				printf("%d",od);
			}
			else{
				printf(" %d",od);
			}
		}
		printf("\n");
		for(i=0;i<lg.vex;i++){
			id =0;
			p = lg.vnodes[i].outhead;
			while(p!=NULL){
				id ++;
				p = p->next_arcnode;
			}
			if(i==0){
				printf("%d",id);
			}
			else{
				printf(" %d",id);
			}
		}
		printf("\n");
		free_lg(&lg);
	}
	return 0;
}