✨ 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/Cargo.toml

@@ -124,6 +124,16 @@ path = "chapter_stack_and_queue/array_stack.rs"
 name = "array_queue"
 path = "chapter_stack_and_queue/array_queue.rs"
 
+# Run Command: cargo run --bin binary_tree_bfs
+[[bin]]
+name = "binary_tree_bfs"
+path = "chapter_tree/binary_tree_bfs.rs"
+
+# Run Command: cargo run --bin binary_tree_dfs
+[[bin]]
+name = "binary_tree_dfs"
+path = "chapter_tree/binary_tree_dfs.rs"
+
 # Run Command: cargo run --bin binary_tree
 [[bin]]
 name = "binary_tree"

codes/rust/chapter_tree/binary_tree_bfs.rs

@@ -0,0 +1,42 @@
+/**
+ * File: binary_tree_bfs.rs
+ * Created Time: 2023-04-07
+ * Author: xBLACKICEx (xBLACKICE@outlook.com)
+ */
+
+use std::collections::VecDeque;
+use std::{cell::RefCell, rc::Rc};
+use tree_node::{vec_to_tree, TreeNode};
+include!("../include/include.rs");
+
+fn level_order(root: &Rc<RefCell<TreeNode>>) -> Vec<i32> {
+    // 初始化队列，加入根结点
+    let mut que = VecDeque::new();
+    que.push_back(Rc::clone(&root));
+    // 初始化一个列表，用于保存遍历序列
+    let mut vec = Vec::new();
+
+    while let Some(node) = que.pop_front() {                // 队列出队
+        vec.push(node.borrow().val);                        // 保存结点值
+        if let Some(left) = node.borrow().left.as_ref() {
+            que.push_back(Rc::clone(left));                 // 左子结点入队
+        }
+        if let Some(right) = node.borrow().right.as_ref() {
+            que.push_back(Rc::clone(right));                // 右子结点入队
+        };
+    }
+    vec
+}
+
+/* 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]).unwrap();
+    println!("初始化二叉树\n");
+    print_util::print_tree(&root);
+
+    /* 层序遍历 */
+    let vec = level_order(&root);
+    print!("\n层序遍历的结点打印序列 = {:?}", vec);
+}

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);
+}

codes/rust/include/tree_node.rs

@@ -5,6 +5,7 @@
  */
 
 use std::cell::RefCell;
+use std::collections::VecDeque;
 use std::rc::Rc;
 
 #[allow(dead_code)]
@@ -27,3 +28,73 @@ impl TreeNode {
         }))
     }
 }
+
+#[macro_export]
+macro_rules! op_vec {
+    ( $( $x:expr ),* ) => {
+        vec![
+            $( Option::from($x).map(|x| x) ),* 
+        ]
+    };
+}
+
+/// This function takes a vector of integers and generates a binary tree from it in a level order traversal manner.
+/// The first element of the vector is used as the root node of the tree. Each node in the tree is represented by a `TreeNode` struct that has a value and pointers to its left and right children.
+///
+/// # Arguments
+///
+/// * `list` - A vector of integers to be used to generate the binary tree.
+///
+/// # Returns
+///
+/// An `Option<Rc<RefCell<TreeNode>>>` where the `Option` is `None` if the vector is empty, and `Some` containing the root node of the tree otherwise.
+///
+/// # Examples
+///
+/// ```
+/// use std::rc::Rc;
+/// use std::cell::RefCell;
+/// use std::collections::VecDeque;
+///
+/// let list = vec![1, 2, 3, 4, 5, 6, 7];
+/// let root = vec_to_tree(list).unwrap();
+///
+/// // The resulting tree looks like:
+/// //
+/// //        1
+/// //       / \
+/// //      2   3
+/// //     / \ / \
+/// //    4   56  7
+/// ```
+pub fn vec_to_tree(list: Vec<Option<i32>>) -> Option<Rc<RefCell<TreeNode>>> {
+    if list.is_empty() {
+        return None;
+    }
+
+    let root = TreeNode::new(list[0].unwrap());
+    let mut que = VecDeque::new();
+    que.push_back(Rc::clone(&root));
+
+    let mut index = 0;
+    while let Some(node) = que.pop_front() {
+        index += 1;
+        if index >= list.len() {
+            break;
+        }
+        if let Some(val) = list[index] {
+            node.borrow_mut().left = Some(TreeNode::new(val));
+            que.push_back(Rc::clone(&node.borrow().left.as_ref().unwrap()));
+        }
+
+        index += 1;
+        if index >= list.len() {
+            break;
+        }
+        if let Some(val) = list[index] {
+            node.borrow_mut().right = Some(TreeNode::new(val));
+            que.push_back(Rc::clone(&node.borrow().right.as_ref().unwrap()));
+        }
+    }
+    Some(root)
+}