20240220 Finished

src/problem/mod.rs

@@ -50,3 +50,4 @@ mod p987_vertical_order_traversal_of_a_binary_tree;
 mod p102_binary_tree_level_order_traversal;
 mod p107_binary_tree_level_order_traversal_ii;
 mod p103_binary_tree_zigzag_level_order_traversal;
+mod p105_construct_binary_tree_from_preorder_and_inorder_traversal;

src/problem/p105_construct_binary_tree_from_preorder_and_inorder_traversal.rs

@@ -0,0 +1,87 @@
+/**
+ * [105] Construct Binary Tree from Preorder and Inorder Traversal
+ */
+pub struct Solution {}
+
+use surf::middleware::logger::new;
+
+use crate::util::tree::{TreeNode, to_tree};
+
+// submission codes start here
+
+// Definition for a binary tree node.
+// #[derive(Debug, PartialEq, Eq)]
+// pub struct TreeNode {
+//   pub val: i32,
+//   pub left: Option<Rc<RefCell<TreeNode>>>,
+//   pub right: Option<Rc<RefCell<TreeNode>>>,
+// }
+//
+// impl TreeNode {
+//   #[inline]
+//   pub fn new(val: i32) -> Self {
+//     TreeNode {
+//       val,
+//       left: None,
+//       right: None
+//     }
+//   }
+// }
+use std::rc::Rc;
+use std::cell::RefCell;
+impl Solution {
+    pub fn build_tree(preorder: Vec<i32>, inorder: Vec<i32>) -> Option<Rc<RefCell<TreeNode>>> {
+        if preorder.len() == 0 {
+            return None;
+        }
+
+        let root = Rc::new(RefCell::new(
+            TreeNode::new(preorder[0])));
+        let mut stack = Vec::new();
+        stack.push(Rc::clone(&root));
+        let mut inorder_index = 0;
+
+        for i in 1..preorder.len() {
+            let mut node = Rc::clone(stack.last().unwrap());
+
+            if node.borrow().val != inorder[inorder_index] {
+                let new_node = Rc::new(RefCell::new(
+                    TreeNode::new(preorder[i])));
+                stack.push(Rc::clone(&new_node));
+                node.borrow_mut().left = Some(new_node);
+            } else {
+                while let Some(top) = stack.last() {
+                    if top.borrow().val == inorder[inorder_index] {
+                        node = Rc::clone(top);
+                        stack.pop();
+                        inorder_index += 1;
+                    } else {
+                        break;
+                    }
+                }
+
+                let new_node = Rc::new(RefCell::new(
+                    TreeNode::new(preorder[i])));
+                stack.push(Rc::clone(&new_node));
+                node.borrow_mut().right = Some(new_node);
+            }
+        }
+
+        Some(root)
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_105() {
+        assert_eq!(Solution::build_tree(
+            vec![3,9,20,15,7],
+            vec![9,3,15,20,7]),
+        to_tree(vec![Some(3), Some(9), Some(20), None, None, Some(15), Some(7)]));
+    }
+}