def only_ones_should_return_zero_test(self):
l = [1] * 10
sum = 6
ans = count_pairs(l, sum)
assert ans == 0
def negative_test(self):
l = [-1, 7, 106, -100, -3, 9]
sum = 6
ans = count_pairs(l, sum)
# (-1,7)
# (-100. 106)
# (-3,9)
assert ans == 3
def basic_test(self):
l = [1,2,2,2,4,5]
sum = 6
ans = count_pairs(l, sum)
# (1,5)
# (2,4)
# (2,4)
# (2,4)
assert ans == 4
def sequence_test(self):
l = [n for n in range(10)]
sum = 6
ans = count_pairs(l, sum)
# (0,6)
# (1,5)
# (2,4)
print(ans)
assert ans == 3
def only_threes_test(self):
l = [3,3,3,3]
sum = 6
ans = count_pairs(l, sum)
# 3 pairs with first 3
# (l[0],l[1])
# (l[0],l[2])
# (l[0],l[3])
# 2 pairs with second 3
# (l[1],l[2])
# (l[1],l[3])
# 1 pair with third and fourth 3
# (l[2],l[3])
# 3 + 2 + 1 = 6 pairs
assert ans == 6
def only_twos_and_fours_test(self):
l = [2,2,2,4,4,4]
sum = 6
ans = count_pairs(l, sum)
# first 2
# (2,4)
# (2,4)
# (2,4)
# second 2
# (2,4)
# (2,4)
# (2,4)
# third 2
# (2,4)
# (2,4)
# (2,4)
#
# E.g. (2,4) for each 2 for each 4 = 3 * 3 = 9
assert ans == 9
def one_item_list_should_return_zero_test(self):
ans = count_pairs([1], 6)
assert ans == 0
def empty_list_should_return_zero_test(self):
ans = count_pairs([], 6)
assert ans == 0