import collections
import util
def jolt_differences(adapters):
adapters = sorted(adapters)
differences = collections.Counter(adapters[i] -
(adapters[i - 1] if i else 0)
for i in range(0, len(adapters)))
differences[3] += 1
return differences[1] * differences[3]
if __name__ == "__main__":
print(jolt_differences(util.readints()))
import day15a
import util
if __name__ == "__main__":
print(day15a.elfgame(util.readints(), endround=30000000))
import functools
import util
def next_possible(adapters, start):
i = start + 1
while i < len(adapters) and adapters[i] - adapters[start] <= 3:
yield i
i += 1
def count_possible(adapters):
adapters = sorted(adapters)
adapters.insert(0, 0)
@functools.lru_cache
def count_possible_from(start):
if start == len(adapters) - 1:
return 1
return sum(
count_possible_from(i) for i in next_possible(adapters, start))
return count_possible_from(0)
if __name__ == "__main__":
print(count_possible(util.readints()))
import day01a
import util
if __name__ == "__main__":
print(day01a.day1(util.readints(), 2020, size=3))
import util
def say(n, r, n2r):
prev_r = n2r.get(n, r)
n2r[n] = r
return r - prev_r, r + 1
def elfgame(numbers, endround=2020):
n2r = {}
r = 1
for start_n in numbers:
n, r = say(start_n, r, n2r)
while r < endround:
n, r = say(n, r, n2r)
return n
if __name__ == "__main__":
print(elfgame(util.readints()))
import itertools
import util
def day1(numbers, key, size=2):
for combination in itertools.combinations(numbers, size):
if sum(combination) == key:
return util.prod(combination)
raise SystemExit("No solution found")
if __name__ == "__main__":
print(day1(util.readints(), 2020, size=2))
import day09a
import util
def find_continuous_set(numbers, target):
for i in range(len(numbers)):
total = numbers[i]
for j in range(i + 1, len(numbers)):
total += numbers[j]
if total == target:
continuous_set = sorted(numbers[i:j + 1])
return continuous_set[0] + continuous_set[-1]
if total > target:
break
raise SystemExit("No solution found")
if __name__ == "__main__":
numbers = list(util.readints())
target = day09a.find_invalid(numbers, 25)
print(find_continuous_set(numbers, target))