Day3. Start Algorithm

21. Merge Two Sorted Lists/Solution.cs

@@ -0,0 +1,44 @@
+namespace _21._Merge_Two_Sorted_Lists;
+
+public class Solution
+{
+    public ListNode MergeTwoLists(ListNode? list1, ListNode? list2)
+    {
+        ListNode? start = null;
+        ListNode? current = null;
+        List<ListNode?> listNodes = new List<ListNode?>() { list1, list2 };
+        while (listNodes.Any(l => l != null))
+        {
+            int i = MinIndex(listNodes);
+            ListNode? curMin = listNodes[i];
+            listNodes[i] = listNodes[i]!.next;
+
+            if (start == null)
+            {
+                start = curMin;
+                current = start;
+            }
+            else if (current != null)
+            {
+                current.next = curMin;
+                current = current.next;
+            }
+        }
+        return start!;
+    }
+
+    private int MinIndex(List<ListNode?> list)
+    {
+        int minValue = int.MaxValue;
+        int index = -1;
+        for (int i = 0; i < list.Count; i++)
+        {
+            if (list[i]?.val < minValue)
+            {
+                minValue = list[i]!.val;
+                index = i;
+            }
+        }
+        return index;
+    }
+}