92 lines
2.7 KiB
Python
92 lines
2.7 KiB
Python
|
import unittest
|
||
|
|
|
||
|
|
|
||
|
|
################################################################################
|
||
|
|
# Implementation
|
||
|
|
################################################################################
|
||
|
|
def is_first_come_first_served(to, di, xs):
|
||
|
|
# All the guards, assertions we should need.
|
||
|
|
if to == di == xs == []:
|
||
|
|
return True
|
||
|
|
elif to == di == []:
|
||
|
|
return False
|
||
|
|
elif to == []:
|
||
|
|
return di == xs
|
||
|
|
elif to == []:
|
||
|
|
return di == xs
|
||
|
|
elif di == []:
|
||
|
|
return to == xs
|
||
|
|
elif xs == []:
|
||
|
|
return False
|
||
|
|
elif len(xs) != (len(to) + len(di)):
|
||
|
|
return False
|
||
|
|
|
||
|
|
fst, snd = to, di
|
||
|
|
|
||
|
|
if xs[0] == to[0]:
|
||
|
|
fst, snd = to, di
|
||
|
|
elif xs[0] == di[0]:
|
||
|
|
fst, snd = di, to
|
||
|
|
else:
|
||
|
|
return False
|
||
|
|
|
||
|
|
fst_done, snd_done = False, False
|
||
|
|
fi, si = 1, 0
|
||
|
|
|
||
|
|
for i in range(1, len(xs)):
|
||
|
|
# Short-circuit and avoid index-out-of-bounds without introducing overly
|
||
|
|
# defensive, sloppy code.
|
||
|
|
if fst_done:
|
||
|
|
return snd[si:] == xs[i:]
|
||
|
|
elif snd_done:
|
||
|
|
return fst[fi:] == xs[i:]
|
||
|
|
|
||
|
|
if fst[fi] == xs[i]:
|
||
|
|
fi += 1
|
||
|
|
elif snd[si] == xs[i]:
|
||
|
|
si += 1
|
||
|
|
else:
|
||
|
|
return False
|
||
|
|
|
||
|
|
fst_done, snd_done = fi == len(fst), si == len(snd)
|
||
|
|
|
||
|
|
return True
|
||
|
|
|
||
|
|
|
||
|
|
################################################################################
|
||
|
|
# Tests
|
||
|
|
################################################################################
|
||
|
|
class Test(unittest.TestCase):
|
||
|
|
def test_both_registers_have_same_number_of_orders(self):
|
||
|
|
result = is_first_come_first_served([1, 4, 5], [2, 3, 6],
|
||
|
|
[1, 2, 3, 4, 5, 6])
|
||
|
|
self.assertTrue(result)
|
||
|
|
|
||
|
|
def test_registers_have_different_lengths(self):
|
||
|
|
result = is_first_come_first_served([1, 5], [2, 3, 6], [1, 2, 6, 3, 5])
|
||
|
|
self.assertFalse(result)
|
||
|
|
|
||
|
|
def test_one_register_is_empty(self):
|
||
|
|
result = is_first_come_first_served([], [2, 3, 6], [2, 3, 6])
|
||
|
|
self.assertTrue(result)
|
||
|
|
|
||
|
|
def test_served_orders_is_missing_orders(self):
|
||
|
|
result = is_first_come_first_served([1, 5], [2, 3, 6], [1, 6, 3, 5])
|
||
|
|
self.assertFalse(result)
|
||
|
|
|
||
|
|
def test_served_orders_has_extra_orders(self):
|
||
|
|
result = is_first_come_first_served([1, 5], [2, 3, 6],
|
||
|
|
[1, 2, 3, 5, 6, 8])
|
||
|
|
self.assertFalse(result)
|
||
|
|
|
||
|
|
def test_one_register_has_extra_orders(self):
|
||
|
|
result = is_first_come_first_served([1, 9], [7, 8], [1, 7, 8])
|
||
|
|
self.assertFalse(result)
|
||
|
|
|
||
|
|
def test_one_register_has_unserved_orders(self):
|
||
|
|
result = is_first_come_first_served([55, 9], [7, 8], [1, 7, 8, 9])
|
||
|
|
self.assertFalse(result)
|
||
|
|
|
||
|
|
|
||
|
|
unittest.main(verbosity=2)
|