存图

导航：

邻接矩阵：https://www.luogu.com.cn/blog/388651/guan-yu-lin-jie-ju-zhen

邻接链表：https://www.luogu.com.cn/blog/388651/guan-yu-lin-jie-lian-biao

链式前向星：https://www.luogu.com.cn/blog/388651/guan-yu-lian-shi-qian-xiang-xing