From 1d3664aa57c62ab85f3dc5faac83b2a2f215f0e9 Mon Sep 17 00:00:00 2001
From: jackfiled <xcrenchangjun@outlook.com>
Date: Thu, 15 Feb 2024 11:27:21 +0800
Subject: [PATCH] 20240215 Finished

---
 src/problem/mod.rs                            |  3 +-
 ...07_binary_tree_level_order_traversal_ii.rs | 80 +++++++++++++++++++
 2 files changed, 82 insertions(+), 1 deletion(-)
 create mode 100644 src/problem/p107_binary_tree_level_order_traversal_ii.rs

diff --git a/src/problem/mod.rs b/src/problem/mod.rs
index ed75eb9..68c6dc1 100644
--- a/src/problem/mod.rs
+++ b/src/problem/mod.rs
@@ -47,4 +47,5 @@ mod p94_binary_tree_inorder_traversal;
 mod p144_binary_tree_preorder_traversal;
 mod p145_binary_tree_postorder_traversal;
 mod p987_vertical_order_traversal_of_a_binary_tree;
-mod p102_binary_tree_level_order_traversal;
\ No newline at end of file
+mod p102_binary_tree_level_order_traversal;
+mod p107_binary_tree_level_order_traversal_ii;
\ No newline at end of file
diff --git a/src/problem/p107_binary_tree_level_order_traversal_ii.rs b/src/problem/p107_binary_tree_level_order_traversal_ii.rs
new file mode 100644
index 0000000..37f0ded
--- /dev/null
+++ b/src/problem/p107_binary_tree_level_order_traversal_ii.rs
@@ -0,0 +1,80 @@
+/**
+ * [107] Binary Tree Level Order Traversal II
+ */
+pub struct Solution {}
+
+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;
+use std::collections::VecDeque;
+
+impl Solution {
+    pub fn level_order_bottom(root: Option<Rc<RefCell<TreeNode>>>) -> Vec<Vec<i32>> {
+        let root = if let Some(r) = root {
+            r
+        } else {
+            return vec![];
+        };
+
+        let mut result = Vec::new();
+        let mut queue = VecDeque::new();
+        queue.push_back(root);
+
+        while !queue.is_empty() {
+            let mut level = Vec::with_capacity(queue.len());
+            for _ in 0..queue.len() {
+                if let Some(node) = queue.pop_front() {
+                    level.push(node.borrow().val);
+
+                    if let Some(left) = &node.borrow().left {
+                        queue.push_back(Rc::clone(left));
+                    }
+
+                    if let Some(right) = &node.borrow().right {
+                        queue.push_back(Rc::clone(right));
+                    }
+                }
+            }
+
+            result.push(level);
+        }
+
+        result.reverse();
+        result
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_107() {
+        assert_eq!(Solution::level_order_bottom(
+            to_tree(vec![Some(3), Some(9), Some(20), None, None, Some(15), Some(7)])
+        ), vec![vec![15, 7], vec![9, 20], vec![3]]);
+    }
+}