✨ feat(rust/tree): add binary_tree_bfs, binary_tree_dfs, (#450)

* ✨ feat(rust/tree): add binary_tree_dfs

* ✨ feat(rust/tree): add binary_tree_bfs

* 🐞 fix(rust/tree): can't list to any kind of tree

codes/rust/chapter_tree/binary_tree_dfs.rs

@@ -0,0 +1,70 @@
+/**
+ * File: binary_tree_dfs.rs
+ * Created Time: 2023-04-06
+ * Author: xBLACKICEx (xBLACKICE@outlook.com)
+ */
+
+use std::cell::RefCell;
+use std::rc::Rc;
+use tree_node::{vec_to_tree, TreeNode};
+include!("../include/include.rs");
+
+/* 前序遍历 */
+fn pre_order(root: Option<&Rc<RefCell<TreeNode>>>) -> Vec<i32> {
+    let mut result = vec![];
+
+    if let Some(node) = root {
+        // 访问优先级：根结点 -> 左子树 -> 右子树
+        result.push(node.borrow().val);
+        result.append(&mut pre_order(node.borrow().left.as_ref()));
+        result.append(&mut pre_order(node.borrow().right.as_ref()));
+    }
+    result
+}
+
+/* 中序遍历 */
+fn in_order(root: Option<&Rc<RefCell<TreeNode>>>) -> Vec<i32> {
+    let mut result = vec![];
+
+    if let Some(node) = root {
+        // 访问优先级：左子树 -> 根结点 -> 右子树
+        result.append(&mut in_order(node.borrow().left.as_ref()));
+        result.push(node.borrow().val);
+        result.append(&mut in_order(node.borrow().right.as_ref()));
+    }
+    result
+}
+
+/* 后序遍历 */
+fn post_order(root: Option<&Rc<RefCell<TreeNode>>>) -> Vec<i32> {
+    let mut result = vec![];
+
+    if let Some(node) = root {
+        // 访问优先级：左子树 -> 右子树 -> 根结点
+        result.append(&mut post_order(node.borrow().left.as_ref()));
+        result.append(&mut post_order(node.borrow().right.as_ref()));
+        result.push(node.borrow().val);
+    }
+    result
+}
+
+/* Driver Code */
+fn main() {
+    /* 初始化二叉树 */
+    // 这里借助了一个从数组直接生成二叉树的函数
+    let root = vec_to_tree(op_vec![1, 2, 3, 4, 5, 6, 7]);
+    println!("初始化二叉树\n");
+    print_util::print_tree(root.as_ref().unwrap());
+
+    /* 前序遍历 */
+    let vec = pre_order(root.as_ref());
+    println!("\n前序遍历的结点打印序列 = {:?}", vec);
+
+    /* 中序遍历 */
+    let vec = in_order(root.as_ref());
+    println!("\n中序遍历的结点打印序列 = {:?}", vec);
+
+    /* 后序遍历 */
+    let vec = post_order(root.as_ref());
+    print!("\n后序遍历的结点打印序列 = {:?}", vec);
+}