Merge pull request #1771 from fwqaaq/master

Update 0106.从中序与后序遍历序列构造二叉树.md about rust

problems/0106.从中序与后序遍历序列构造二叉树.md

@@ -1149,6 +1149,52 @@ object Solution {
 }
 ```
 
+## rust
+
+106 从中序与后序遍历序列构造二叉树
+
+```rust
+use std::cell::RefCell;
+use std::rc::Rc;
+impl Solution {
+    pub fn build_tree(inorder: Vec<i32>, postorder: Vec<i32>) -> Option<Rc<RefCell<TreeNode>>> {
+        if inorder.is_empty() {
+            return None;
+        }
+        let mut postorder = postorder;
+        let root = postorder.pop().unwrap();
+        let index = inorder.iter().position(|&x| x == root).unwrap();
+        let mut root = TreeNode::new(root);
+        root.left = Self::build_tree(inorder[..index].to_vec(), postorder[..index].to_vec());
+        root.right = Self::build_tree(inorder[index + 1..].to_vec(), postorder[index..].to_vec());
+        Some(Rc::new(RefCell::new(root)))
+    }
+}
+```
+
+105 从前序与中序遍历序列构造二叉树
+
+```rust
+use std::cell::RefCell;
+use std::rc::Rc;
+impl Solution {
+    pub fn build_tree(preorder: Vec<i32>, inorder: Vec<i32>) -> Option<Rc<RefCell<TreeNode>>> {
+        if preorder.is_empty() {
+            return None;
+        }
+        let root = preorder[0];
+        let index = inorder.iter().position(|&x| x == root).unwrap();
+        let mut root = TreeNode::new(root);
+        root.left = Self::build_tree(preorder[1..index + 1].to_vec(), inorder[0..index].to_vec());
+        root.right = Self::build_tree(
+            preorder[index + 1..].to_vec(),
+            inorder[index + 1..].to_vec(),
+        );
+        Some(Rc::new(RefCell::new(root)))
+    }
+}
+```
+
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