feat: add dart code for chapter_graph

[gvenusleo]

If this PR is related to coding or code translation, please fill out the checklist and paste the console outputs to the PR.

• [x] I've tested the code and ensured the outputs are the same as the outputs of reference codes.
• [x] I've checked the codes (formatting, comments, indentation, file header, etc) carefully.
• [x] The code does not rely on a particular environment or IDE and can be executed on a standard system (Win, macOS, Ubuntu).

[vercel[bot]]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

1 Ignored Deployment

Name	Status	Preview	Comments	Updated (UTC)
hello-algo	⬜️ Ignored (Inspect)			May 15, 2023 9:48am

[gvenusleo]

Here is the terminal output.

graph_adjacency_list.dart

初始化后，图为
邻接表 =
1: [3, 5],
3: [1, 2],
5: [1, 2, 4],
2: [3, 5, 4],
4: [2, 5],

添加边 1-2 后，图为
邻接表 =
1: [3, 5, 2],
3: [1, 2],
5: [1, 2, 4],
2: [3, 5, 4, 1],
4: [2, 5],

删除边 1-3 后，图为
邻接表 =
1: [5, 2],
3: [2],
5: [1, 2, 4],
2: [3, 5, 4, 1],
4: [2, 5],

添加顶点 6 后，图为
邻接表 =
1: [5, 2],
3: [2],
5: [1, 2, 4],
2: [3, 5, 4, 1],
4: [2, 5],
6: [],

删除顶点 3 后，图为
邻接表 =
1: [5, 2],
5: [1, 2, 4],
2: [5, 4, 1],
4: [2, 5],
6: [],

graph_adjacency_matrix.dart

初始化后，图为
顶点列表 =
[1, 3, 2, 5, 4]
邻接矩阵 = 
[
  [0, 1, 0, 1, 0],
  [1, 0, 1, 0, 0],
  [0, 1, 0, 1, 1],
  [1, 0, 1, 0, 1],
  [0, 0, 1, 1, 0],
]

添加边 1-2 后，图为
顶点列表 = 
[1, 3, 2, 5, 4]
邻接矩阵 = 
[
  [0, 1, 1, 1, 0],
  [1, 0, 1, 0, 0],
  [1, 1, 0, 1, 1],
  [1, 0, 1, 0, 1],
  [0, 0, 1, 1, 0],
]

删除边 1-3 后，图为
顶点列表 = 
[1, 3, 2, 5, 4]
邻接矩阵 = 
[
  [0, 0, 1, 1, 0],
  [0, 0, 1, 0, 0],
  [1, 1, 0, 1, 1],
  [1, 0, 1, 0, 1],
  [0, 0, 1, 1, 0],
]

添加顶点 6 后，图为
顶点列表 = 
[1, 3, 2, 5, 4, 6]
邻接矩阵 = 
[
  [0, 0, 1, 1, 0, 0],
  [0, 0, 1, 0, 0, 0],
  [1, 1, 0, 1, 1, 0],
  [1, 0, 1, 0, 1, 0],
  [0, 0, 1, 1, 0, 0],
  [0, 0, 0, 0, 0, 0],
]

删除顶点 3 后，图为
顶点列表 = 
[1, 2, 5, 4, 6]
邻接矩阵 = 
[
  [0, 1, 1, 0, 0],
  [1, 0, 1, 1, 0],
  [1, 1, 0, 1, 0],
  [0, 1, 1, 0, 0],
  [0, 0, 0, 0, 0],
]

graph_bfs.dart

初始化后，图为
邻接表 =
0: [1, 3],
1: [0, 2, 4],
3: [0, 4, 6],
2: [1, 5],
4: [1, 3, 5, 7],
5: [2, 4, 8],
6: [3, 7],
7: [4, 6, 8],
8: [5, 7],

广度优先遍历（BFS）顶点序列为
[0, 1, 3, 2, 4, 6, 5, 7, 8]

graph_dfs.dart

初始化后，图为
邻接表 =
0: [1, 3],
1: [0, 2],
3: [0],
2: [1, 5],
5: [2, 4, 6],
4: [5],
6: [5],

深度优先遍历（DFS）顶点序列为
[0, 1, 2, 5, 4, 6, 3]