[DaleSeo] WEEK 04 solutions

merge-two-sorted-lists/DaleSeo.rs

@@ -0,0 +1,24 @@
+// TC: O(m + n)
+// SC: O(1)
+impl Solution {
+    pub fn merge_two_lists(list1: Option<Box<ListNode>>, list2: Option<Box<ListNode>>) -> Option<Box<ListNode>> {
+        let mut dummy = Box::new(ListNode::new(-1));
+        let mut node = &mut dummy;
+        let (mut l1, mut l2) = (list1, list2);
+        while l1.is_some() && l2.is_some() {
+            let val1 = l1.as_ref().unwrap().val;
+            let val2 = l2.as_ref().unwrap().val;
+            if val1 < val2 {
+                node.next = l1;
+                node = node.next.as_mut().unwrap();
+                l1 = node.next.take();
+            } else {
+                node.next = l2;
+                node = node.next.as_mut().unwrap();
+                l2 = node.next.take();
+            }
+        }
+        node.next = l1.or(l2);
+        dummy.next
+    }
+}