feat: Revised the book (#978)

* Sync recent changes to the revised Word.

* Revised the preface chapter

* Revised the introduction chapter

* Revised the computation complexity chapter

* Revised the chapter data structure

* Revised the chapter array and linked list

* Revised the chapter stack and queue

* Revised the chapter hashing

* Revised the chapter tree

* Revised the chapter heap

* Revised the chapter graph

* Revised the chapter searching

* Reivised the sorting chapter

* Revised the divide and conquer chapter

* Revised the chapter backtacking

* Revised the DP chapter

* Revised the greedy chapter

* Revised the appendix chapter

* Revised the preface chapter doubly

* Revised the figures

codes/csharp/chapter_graph/graph_bfs.cs

@@ -23,7 +23,7 @@ public class graph_bfs {
             res.Add(vet);               // 记录访问顶点
             foreach (Vertex adjVet in graph.adjList[vet]) {
                 if (visited.Contains(adjVet)) {
-                    continue;          // 跳过已被访问过的顶点
+                    continue;          // 跳过已被访问的顶点
                 }
                 que.Enqueue(adjVet);   // 只入队未访问的顶点
                 visited.Add(adjVet);   // 标记该顶点已被访问