feat: add rust codes for graph chapter (#598)

* feat: add rust codes for graph chapter

* update: remove Vertex and it's method to vertex.rs

codes/rust/chapter_graph/graph_dfs.rs

@@ -0,0 +1,61 @@
+/*
+ * File: graph_dfs.rs
+ * Created Time: 2023-07-12
+ * Author: night-cruise (2586447362@qq.com)
+ */
+
+mod graph_adjacency_list;
+
+use std::collections::HashSet;
+use graph_adjacency_list::GraphAdjList;
+use graph_adjacency_list::{Vertex, vets_to_vals, vals_to_vets};
+
+/* 深度优先遍历 DFS 辅助函数 */
+fn dfs(graph: &GraphAdjList, visited: &mut HashSet<Vertex>, res: &mut Vec<Vertex>, vet: Vertex) {
+    res.push(vet); // 记录访问顶点
+    visited.insert(vet); // 标记该顶点已被访问
+                         // 遍历该顶点的所有邻接顶点
+    if let Some(adj_vets) = graph.adj_list.get(&vet) {
+        for &adj_vet in adj_vets {
+            if visited.contains(&adj_vet) {
+                continue; // 跳过已被访问过的顶点
+            }
+            // 递归访问邻接顶点
+            dfs(graph, visited, res, adj_vet);
+        }
+    }
+}
+
+/* 深度优先遍历 DFS */
+// 使用邻接表来表示图，以便获取指定顶点的所有邻接顶点
+fn graph_dfs(graph: GraphAdjList, start_vet: Vertex) -> Vec<Vertex> {
+    // 顶点遍历序列
+    let mut res = vec![];
+    // 哈希表，用于记录已被访问过的顶点
+    let mut visited = HashSet::new();
+    dfs(&graph, &mut visited, &mut res, start_vet);
+
+    res
+}
+
+/* Driver Code */
+fn main() {
+    /* 初始化无向图 */
+    let v = vals_to_vets(vec![0, 1, 2, 3, 4, 5, 6]);
+    let edges = vec![
+        [v[0], v[1]],
+        [v[0], v[3]],
+        [v[1], v[2]],
+        [v[2], v[5]],
+        [v[4], v[5]],
+        [v[5], v[6]],
+    ];
+    let graph = GraphAdjList::new(edges);
+    println!("\n初始化后，图为");
+    graph.print();
+
+    /* 深度优先遍历 DFS */
+    let res = graph_dfs(graph, v[0]);
+    println!("\n深度优先遍历（DFS）顶点序列为");
+    println!("{:?}", vets_to_vals(res));
+}