1. CH05 Graph
   1. define
      1. vertices,頂點
      2. edges,邊
      3. adjacent,相鄰
      4. path
      5. cycle,環路
      6. subgraph
      7. connected graph
      8. degree
         1. indegree
         2. outdegree
      9. undirected graph
         1. connected graph
         2. complete graph
      10. directed graph
          1. head
          2. tail
          3. strongly connected graph
          4. complete graph
   2. adjacency matrix
      1. 無向圖
         1. 一定是對稱矩陣
      2. 有向圖
         1. 不一定是對稱矩陣
      3. 對角線一定為零
   3. adjacency list
      1. 無向圖
         1. 總節點數是邊數兩倍
            1. 因為是雙向
      2. 有向圖
         1. 總節點數等於邊數
   4. weighted graph
   5. traversal
      1. Breadth First Search
         1. 水波
            1. queue
      2. Depth First Search
         1. 河流
            1. stack
   6. spanning tree
      1. kruskal 演算法
      2. prim 演算法