#!/usr/bin/python

class ListNode(object):
    def __init__(self,val):
        self.val = val
        self.next = None # the pointer initially points to nothing

def addTwoNumbers(l1, l2):
    """
    :type l1: ListNode
    :type l2: ListNode
    :rtype: ListNode
    """
    r = None
    rd = 0 # round
    while l1 != None or l2 != None:
        temp = rd
        if l1 != None:
            temp += l1.val
        if l2 != None:
            temp += l2.val
        if temp >= 10:
            temp -= 10
            rd = 1
        else:
            rd = 0
        if r == None:
            n = ListNode(temp)
            r = n
        else:
            m = ListNode(temp)
            n.next = m;
            n = m;
        if l1 != None:
            l1 = l1.next
        if l2 != None:
            l2 = l2.next
    if rd > 0:
        n.next = Node(1)
    return r

def displayList(l):
    while l != None:
        print l.val,
        l = l.next
    print

if __name__ == '__main__':
    n1 = ListNode(2)
    n2 = ListNode(4)
    n3 = ListNode(3); 
    n1.next = n2
    n2.next = n3

    l1 = n1

    n4 = ListNode(5)
    n5 = ListNode(6)
    n6 = ListNode(4)
    n4.next = n5
    n5.next = n6

    l2 = n4

    r = addTwoNumbers(l1, l2)

    displayList(l1)
    displayList(l2)
    displayList(r)
			

#!/usr/bin/python

class ListNode(object):
    def __init__(self,val):
        self.val = val
        self.next = None # the pointer initially points to nothing

def addTwoNumbers(l1, l2):
    """
    :type l1: ListNode
    :type l2: ListNode
    :rtype: ListNode
    """
    r = ListNode(0) # initial round to be zero
    temp = r
    while l1 != None or l2 != None:
        temp.val = l1.val + l2.val + temp.val
        if temp.val >= 10:
            temp.val -= 10
            temp.next = ListNode(1)
        l1 = l1.next
        l2 = l2.next
        if l1 == None or l2 == None:
            break
        if temp.next == None:
            temp.next = ListNode(0)
        temp = temp.next
    if l1 != None:
        if temp.next != None:
            temp.next = addTwoNumbers(l1, temp.next)
        else:
            temp.next = l1
    if l2 != None:
        if temp.next != None:
            temp.next = addTwoNumbers(temp.next, l2)
        else:
            temp.next = l2
    return r

def displayList(l):
    while l != None:
        print(l.val, end=', ')
        l = l.next
    print()

if __name__ == '__main__':
    n1 = ListNode(2)
    n2 = ListNode(4)
    n3 = ListNode(3); 
    n1.next = n2
    n2.next = n3

    l1 = n1

    n4 = ListNode(5)
    n5 = ListNode(6)
    n6 = ListNode(4)
    n4.next = n5
    n5.next = n6

    l2 = n4

    r = addTwoNumbers(l1, l2)

    displayList(l1)
    displayList(l2)
    displayList(r)