aoc2020/day15/day15.py

27 lines
609 B
Python

#!/usr/bin/env python
import sys
def run_game(init, iterations):
last_seen = {}
previous = None
for i, n in enumerate(init):
if previous is not None:
last_seen[previous] = i-1
previous = n
for i in range(i+1, iterations):
if previous in last_seen:
x = i - last_seen[previous] - 1
else:
x = 0
last_seen[previous] = i-1
previous = x
return previous
if __name__ == '__main__':
init = [int(n) for n in sys.stdin.read().split(',')]
print(run_game(init, 2020))
print(run_game(init, 30000000))