added daily challenge

Author: Pasindu-Vishmika

1669. Merge In Between Linked Lists.py

@@ -0,0 +1,34 @@
+# Definition for singly-linked list.
+# class ListNode:
+#     def __init__(self, val=0, next=None):
+#         self.val = val
+#         self.next = next
+class Solution:
+    def mergeInBetween(self, list1: ListNode, a: int, b: int, list2: ListNode) -> ListNode:
+        prev = list1
+        temp1 = list1
+        curr = list1
+        a -= 1  
+        
+        while temp1 and a > 0:
+            temp1 = temp1.next
+            prev = temp1
+            a -= 1
+        
+        temp1 = list1  
+        
+
+        while temp1 and b > 0:
+            temp1 = temp1.next
+            curr = temp1
+            b -= 1
+        
+        temp2 = list2  
+        
+        while temp2.next:
+            temp2 = temp2.next
+        
+        prev.next = list2  
+        temp2.next = curr.next 
+        
+        return list1