Given a linked list of integers, remove all consecutive nodes that sum up to n.

remove-consecutive-sum-to-n.py

class Node():
  def __init__(self, value, next=None):
    self.value = value
    self.next = next

# returns a node if the sum is n
def sumTo(n, node):
  s = 0
  while node != None:
    s = s + node.value
    if s == n:
      return node #found
    node = node.next
  return None # not found

def removeConsecutiveSumToN(n, node):
  prev = None
  while node != None:
    nn = sumTo(0, node)
    if nn!= None: #found
      if prev != None:
        prev.next = nn.next
      else:
        prev = nn.next
      node = nn.next
    else:
      prev = node
      node = node.next 
  return prev

def printNode(node):
  while node:
    print(node.value)
    node = node.next

def test1():
  print("test1")
  node = Node(10)
  node = removeConsecutiveSumToN(0, node)
  printNode(node)

def test2():
  print("test2")
  node = Node(10)
  node.next = Node(-10)
  node = removeConsecutiveSumToN(0, node)
  printNode(node)

def test3():
  print("test3")
  node = Node(10)
  node.next = Node(-10)
  node.next.next = Node(2)
  node = removeConsecutiveSumToN(0, node)
  printNode(node)

def test4():
  print("test4")
  node = Node(10)
  node.next = Node(5)
  node.next.next = Node(-3)
  node.next.next.next = Node(-3)
  node.next.next.next.next = Node(1)
  node.next.next.next.next.next = Node(4)
  node.next.next.next.next.next.next = Node(-4)
  node = removeConsecutiveSumToN(0, node)
  printNode(node)

def main():
  test1()
  test2()
  test3()
  test4()

if __name__ == "__main__":
  main()