chore: add alternate solution to 0707

Author: scarowar

problems/0707-design-linked-list/alternate_solution.py

@@ -0,0 +1,99 @@
+from typing import *
+
+class Node:
+ def __init__(self, val):
+ self.val = val
+ self.next = None
+
+class MyLinkedList:
+
+ def __init__(self):
+ self.head = Node(None)
+ self.tail = self.head
+ self.size = 0
+
+ def get(self, index: int) -> int:
+ if not self.checkElementIndex(index):
+ return -1
+
+ p = self.head.next
+ for _ in range(index):
+ p = p.next
+ 
+ return p.val
+
+
+ def addAtHead(self, val: int) -> None:
+ x = Node(val)
+ 
+ x.next = self.head.next
+ self.head.next = x
+ 
+ if self.size == 0:
+ self.tail = x
+ 
+ self.size += 1
+ 
+
+ def addAtTail(self, val: int) -> None:
+ x = Node(val)
+ self.tail.next = x
+ self.tail = x
+ 
+ self.size += 1
+ 
+
+ def addAtIndex(self, index: int, val: int) -> None:
+ if not self.checkPositionIndex(index):
+ return
+
+ if index == self.size:
+ self.addAtTail(val)
+ return
+
+ prev = self.head
+ 
+ for _ in range(index):
+ prev = prev.next
+ 
+ x = Node(val)
+ 
+ x.next = prev.next
+ prev.next = x
+ 
+ self.size += 1
+
+ def deleteAtIndex(self, index: int) -> None:
+ if not self.checkElementIndex(index):
+ return
+
+ prev = self.head
+ 
+ for _ in range(index):
+ prev = prev.next
+ 
+ node_to_remove = prev.next
+ prev.next = node_to_remove.next
+ 
+ if index == self.size - 1:
+ self.tail = prev
+ 
+ self.size -= 1
+ 
+ return node_to_remove.val
+
+ # utils
+ def checkElementIndex(self, index):
+ return 0 <= index < self.size
+ 
+ def checkPositionIndex(self, index):
+ return 0 <= index <= self.size
+ 
+if __name__ == "__main__":
+ obj = MyLinkedList()
+ obj.addAtHead(1)
+ obj.addAtTail(3)
+ obj.addAtIndex(1, 2)
+ print(obj.get(1))
+ obj.deleteAtIndex(1)
+ print(obj.get(1))