A collection of implementations of common algorithms
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#! /usr/bin/env python3
# reverse a linked list
class LinkedList:
def __init__(self, head, tail):
self.head = head
self.tail = tail
def __repr__(self):
return "%s%s" % (self.head, "" if self.tail is None else ",%s" % repr(self.tail))
def cons(x, xs):
return LinkedList(x, xs)
xs = cons(1, cons(2, cons(3, cons(4, cons(5, None)))))
def push(x, xs):
prev = xs.head
xs.head = x
xs.tail = cons(prev, xs.tail)
def reverseLinkedList(xs):
current = xs.head
rest = xs.tail
revd = None
while True:
if revd is None:
revd = cons(current, None)
push(current, revd)
if rest is None:
current = rest.head
rest = rest.tail
return revd