Adding Efficient Solution for Problem - 19 - Remove Nth Node From End

Author: Vanditg

Remove_Nth_Node_From_End/EfficientSolution.py

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+##==================================
+## Leetcode
+## Student: Vandit Jyotindra Gajjar
+## Year: 2020
+## Problem: 19
+## Problem Name: Remove Nth Node From End of List   
+##===================================
+#
+#Given a linked list, remove the n-th node from the end of list and return its head.
+#
+#Example:
+#
+#Given linked list: 1->2->3->4->5, and n = 2.
+#
+#After removing the second node from the end, the linked list becomes 1->2->3->5.
+class Solution:
+    def removeNthFromEnd(self, head, n):
+        tmp = head	#Initialize tmp 
+        count = 0	#Initialize count
+        while tmp:	#Loop: tmp is not empty, we traverse the list 
+            tmp = tmp.next	#point to next node 
+            count += 1	#Increment count by 1
+        index = count - n	#Initialize index which is given equation's result value 
+        previous = None	#Initialize previous
+		point = head	#Initialize point 
+        while index != 0:	#Loop: index is not zero
+            previous = point	#Assign point to previous
+            point = point.next	#point to next node 
+            index -= 1	#Decrease the index value by 1 
+        if previous is None:	#Condition-check: If previous is empty
+            return head.next 	#Return head.next
+        else: 	#Condition-check: Else 
+            previous.next = point.next		#Point point.next to previous.next
+            point.next = None	#Point point.next to none 
+            return head	#Return head at the end.