sum two lists - v1

others/add_two_integers.py

@@ -0,0 +1,66 @@
+"""
+Problem Statement
+Given the head pointers of two linked lists where each linked list represents an integer number (each node is a digit), 
+add them and return the resulting linked list. Here, the first node in a list represents the least significant digit.
+"""
+class Node:
+	def __init__(self, value):
+		self.value = value
+		self.next = None
+
+def sum_lists(l1, l2):
+	c = 0
+	l3 = None
+	while l1 or l2:
+		v1 = 0
+		v2 = 0
+		if l1:
+			v1 = l1.value
+			l1 = l1.next
+		if l2:
+			v2 = l2.value
+			l2 = l2.next
+		r = v1 + v2 + c
+		c = r // 10
+		d = r % 10
+
+		if not l3:
+			l3 = Node(d)
+			p3 = l3
+		else:
+			p3.next = Node(d)
+			p3 = p3.next
+
+	return l3
+
+def print_list(l):
+	while l:
+		print("{}->".format(l.value), end = '')
+		l = l.next
+
+def print_number(l):
+	stack = []
+	while l:
+		stack.append(l.value)
+		l = l.next
+	while len(stack) > 0:
+		v = stack.pop()
+		print("{}".format(v), end = '')
+
+def create_linked_list(list_numbers):
+	l = None
+	for n in list_numbers:
+		if not l:
+			l = Node(n)
+			p = l
+		else:
+			p.next = Node(n)
+			p = p.next
+	return l 
+
+first = create_linked_list([1, 2, 3]) #321
+second = create_linked_list([1, 2]) #21
+print("Sum:", end='')
+r = sum_lists(first, second)
+print_number(r)
+print()