Added remove nth node from end of a linked-list

omrawal · omrawal · commit 3c473ff4e126 · 2021-08-20T19:09:05.000+05:30
diff --git a/algorithms/linkedlist/delete_nth_node_from_end.py b/algorithms/linkedlist/delete_nth_node_from_end.py
@@ -0,0 +1,32 @@
+# remove nth node from end
+# https://leetcode.com/problems/remove-nth-node-from-end-of-list/
+
+# brute
+# create a new linked list without that element
+# Time O(n)
+# Space O(n)
+
+# optimal
+
+
+# Definition for singly-linked list.
+class ListNode:
+    def __init__(self, val=0, next=None):
+        self.val = val
+        self.next = next
+
+
+class Solution:
+    def removeNthFromEnd(self, head: ListNode, n: int) -> ListNode:
+        if(head.next == None):
+            return None
+        start = ListNode()
+        start.next = head
+        slow = fast = start
+        for i in range(1, n+1):
+            fast = fast.next
+        while(fast.next != None):
+            fast = fast.next
+            slow = slow.next
+        slow.next = slow.next.next
+        return start.next
