leetcode-study (#2631)

Author: DaleSeo

binary-tree-level-order-traversal/DaleSeo.rs

@@ -0,0 +1,31 @@
+// TC: O(n)
+// SC: O(n)
+use std::cell::RefCell;
+use std::collections::VecDeque;
+use std::rc::Rc;
+
+impl Solution {
+    pub fn level_order(root: Option<Rc<RefCell<TreeNode>>>) -> Vec<Vec<i32>> {
+        let mut output = Vec::new();
+        let mut queue = VecDeque::new();
+        if let Some(node) = root {
+            queue.push_back(node);
+        }
+        while !queue.is_empty() {
+            let mut values = Vec::with_capacity(queue.len());
+            for _ in 0..queue.len() {
+                let node = queue.pop_front().unwrap();
+                let node = node.borrow();
+                values.push(node.val);
+                if let Some(left) = node.left.clone() {
+                    queue.push_back(left);
+                }
+                if let Some(right) = node.right.clone() {
+                    queue.push_back(right);
+                }
+            }
+            output.push(values);
+        }
+        output
+    }
+}