Create day8_MiddleoftheLinkedList.py

Author: KB-perByte

Leetcode_30days/day8_MiddleoftheLinkedList.py

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+'''
+Given a non-empty, singly linked list with head node head, return a middle node of linked list.
+
+If there are two middle nodes, return the second middle node.
+'''
+
+# Definition for singly-linked list.
+# class ListNode(object):
+#     def __init__(self, x):
+#         self.val = x
+#         self.next = None
+
+class Solution(object):
+    def middleNode(self, head):
+        """
+        :type head: ListNode
+        :rtype: ListNode
+        """
+        if(head == None): 
+            return None
+        
+        ptr1_node = head 
+        ptr2_node = head 
+        prev = None
+        while(ptr2_node != None and ptr2_node.next != None): 
+            prev = ptr1_node 
+            ptr1_node = ptr1_node.next
+            ptr2_node = ptr2_node.next.next
+            
+        return ptr1_node
+