# Separate the pointers by k-1.
for i in xrange(k-1):
runner = runner.next_node
# Went off the edge: list isn't long enough.
if not runner: return -1
# When runner goes off the end, we know curr is the kth node from the end.
while runner:
curr = curr.next_node
runner = runner.next_node
return curr.data
t1 = Node('a')
t1.next_node = Node('b')
t1.next_node.next_node = Node('c')
t1b = Node('a')
t1b.next_node = Node('b')
t1b.next_node.next_node = Node('c')
print kth_to_last(t1, 2)
print "should be b"
print kth_to_last(t1b, 2)
print "one pass, should be b"
t2 = Node('a')
t2.next_node = Node('b')
t2.next_node.next_node = Node('c')
curr, runner = head, head.next_node
while curr:
runner = curr
while runner.next_node:
if curr.data == runner.next_node.data:
runner.next_node = runner.next_node.next_node
else:
runner = runner.next_node
curr = curr.next_node
# a, a, b | a, b, b, a
t1 = Node('a')
t1.next_node = Node('a')
t1.next_node.next_node = Node('b')
t11 = Node('a')
t11.next_node = Node('a')
t11.next_node.next_node = Node('b')
t2 = Node('a')
t2.next_node = Node('b')
t2.next_node.next_node = Node('b')
t2.next_node.next_node.next_node = Node('a')
t21 = Node('a')
t21.next_node = Node('b')
t21.next_node.next_node = Node('b')
t21.next_node.next_node.next_node = Node('a')
curr, runner = head, head.next_node
while curr:
runner = curr
while runner.next_node:
if curr.data == runner.next_node.data:
runner.next_node = runner.next_node.next_node
else:
runner = runner.next_node
curr = curr.next_node
# a, a, b | a, b, b, a
t1 = Node('a')
t1.next_node = Node('a')
t1.next_node.next_node = Node('b')
t11 = Node('a')
t11.next_node = Node('a')
t11.next_node.next_node = Node('b')
t2 = Node('a')
t2.next_node = Node('b')
t2.next_node.next_node = Node('b')
t2.next_node.next_node.next_node = Node('a')
t21 = Node('a')
t21.next_node = Node('b')
t21.next_node.next_node = Node('b')
t21.next_node.next_node.next_node = Node('a')
def test_creation1(self):
"""Test manual assignment of next node."""
first = Node(100)
second = Node(200)
first.next_node = second
self.assertEqual(first.next_node, second)
# Separate the pointers by k-1.
for i in xrange(k - 1):
runner = runner.next_node
# Went off the edge: list isn't long enough.
if not runner: return -1
# When runner goes off the end, we know curr is the kth node from the end.
while runner:
curr = curr.next_node
runner = runner.next_node
return curr.data
t1 = Node('a')
t1.next_node = Node('b')
t1.next_node.next_node = Node('c')
t1b = Node('a')
t1b.next_node = Node('b')
t1b.next_node.next_node = Node('c')
print kth_to_last(t1, 2)
print "should be b"
print kth_to_last(t1b, 2)
print "one pass, should be b"
t2 = Node('a')
t2.next_node = Node('b')
t2.next_node.next_node = Node('c')