Day 13: Attempt 2: 138_Copy_List_with_Random_Pointer

Readme.md

@@ -20,7 +20,7 @@ LeetCode offers a valuable platform for coding practice and problem-solving, esp
 ## Stay Committed
 Remember, the 75 Hard Challenge is about personal growth and discipline. Stay committed to your goals, and track your journey. You've got this!
 
-## Progress  ![Progress](https://img.shields.io/badge/47%2F150-28a745)
+## Progress  ![Progress](https://img.shields.io/badge/53%2F150-28a745)
 
 
 *In first attempt I solved questions for 21 days*
@@ -53,6 +53,7 @@ Remember, the 75 Hard Challenge is about personal growth and discipline. Stay co
 - Day 12: [141. Linked List Cycle](https://leetcode.com/problems/linked-list-cycle/)
 - Day 12: [2. Add Two Numbers](https://leetcode.com/problems/add-two-numbers/)
 - Day 12: [21. Merge Two Sorted Lists](https://leetcode.com/problems/merge-two-sorted-lists/)
+- Day 13: [138. Copy List with Random Pointer](https://leetcode.com/problems/copy-list-with-random-pointer/)
 
 
 

top_interview_questions/75_hard/Linked List/138_Copy_List_with_Random_Pointer.py

@@ -0,0 +1,39 @@
+"""
+# Definition for a Node.
+class Node:
+    def __init__(self, x: int, next: 'Node' = None, random: 'Node' = None):
+        self.val = int(x)
+        self.next = next
+        self.random = random
+"""
+class Node:
+    def __init__(self, x: int, next: 'Node' = None, random: 'Node' = None):
+        self.val = int(x)
+        self.next = next
+        self.random = random
+
+class Solution:
+    def copyRandomList(self, head: 'Optional[Node]') -> 'Optional[Node]':
+        oldToCopy = {None:None}
+
+        cur = head
+        while cur:
+            copy = Node(cur.val)
+            oldToCopy[cur] = copy
+            cur = cur.next
+
+        cur = head
+        while cur:
+            copy = oldToCopy[cur]
+            copy.next = oldToCopy[cur.next]
+            copy.random = oldToCopy[cur.random]
+            cur = cur.next
+        return oldToCopy[head]
+
+
+
+
+
+sol = Solution()
+head = [[7,None],[13,0],[11,4],[10,2],[1,0]]
+sol.copyRandomList(head=head)

top_interview_questions/75_hard/Linked List/92_Reverse_Linked_List_II.py

@@ -0,0 +1,8 @@
+# Definition for singly-linked list.
+# class ListNode:
+#     def __init__(self, val=0, next=None):
+#         self.val = val
+#         self.next = next
+class Solution:
+    def reverseBetween(self, head: Optional[ListNode], left: int, right: int) -> Optional[ListNode]:
+        pass