revert

Author: songyzh

src/lib.rs

@@ -231,6 +231,7 @@ mod n0199_binary_tree_right_side_view;
 mod n0282_expression_add_operators;
 mod n0021_merge_two_sorted_lists;
 mod n0129_sum_root_to_leaf_numbers;
+mod n0206_reverse_linked_list;
 mod n0131_palindrome_partitioning;
 mod n0307_range_sum_query_mutable;
 mod n0111_minimum_depth_of_binary_tree;

src/n0206_reverse_linked_list.rs

@@ -0,0 +1,50 @@
+/**
+ * [206] Reverse Linked List
+ *
+ * Reverse a singly linked list.
+ *
+ * Example:
+ *
+ *
+ * Input: 1->2->3->4->5->NULL
+ * Output: 5->4->3->2->1->NULL
+ *
+ *
+ * Follow up:
+ *
+ * A linked list can be reversed either iteratively or recursively. Could you implement both?
+ *
+ */
+pub struct Solution {}
+
+use super::util::linked_list::{to_list, ListNode};
+
+// submission codes start here
+
+impl Solution {
+    pub fn reverse_list(head: Option<Box<ListNode>>) -> Option<Box<ListNode>> {
+        let mut curr = head;
+        let mut next = None;
+        while let Some(mut inner) = curr {
+            curr = inner.next.take();
+            inner.next = next;
+            next = Some(inner);
+        }
+        next
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_206() {
+        assert_eq!(
+            Solution::reverse_list(linked![1, 2, 3, 4, 5]),
+            linked![5, 4, 3, 2, 1]
+        );
+    }
+}