图的存储 链表 和 矩阵存储
矩阵存储 ：
#include <stdio.h>
#include <string.h>
int main(){
freopen("M.in", "r", stdin);
freopen("M.out", "w", stdout);
int m, n, map[100][100], u, v, i, j;
while(scanf("%d%d", &n, &m) != -1){
memset(map, 0, sizeof(map));
for(i = 0; i < m; i++){
scanf("%d%d", &u, &v);
map[u][v] = map[v][u] = 1; //代表 u->v v -> u 两条边
}
for(i = 0; i < n; i++){
for(j = 0; j < n; j++)
printf("%d ", map[i][j]);
puts("");
}
}
return 0;
}
链表存储 ：
#include <stdio.h>
#include <string.h>
struct e{
int v;
struct e* next;
};
e* edge[100];
int m, n;
int main(){
freopen("link_new.in", "r", stdin);
freopen("link_new.out", "w", stdout);
int i, j, u, v;
e* node;
while(scanf("%d%d", &n, &m) != -1){
for(i = 0; i < 100; i++)edge[i] = NULL;
for(i = 0; i < m; i++){
scanf("%d%d", &u, &v);
node = new e;
node->v = v;
node->next = edge[u];//只想指针数组所指的链表内第一个元素，其实就相当于记录一下指针数组的所指的位置
edge[u] = node;//把指针数组只想插入的节点，就连接上了。 倒序插入
node = new e;
node->v = u;
node->next = edge[v];
edge[v] = node;
}
for(i = 0; i < n; i++){
node = edge[i];
printf("%d : ", i);
while(node){
printf("%d ", node->v);
node = node -> next;
}
puts("");
}
}
return 0;
}