#advent of code 2024
#day 11
#I liked it. what I did was:
#store current stones in dictionary in format stonenumber:amount of these stones
#iterate the changes in time
#if the given stone is split up for the first time, the result is memorized
#in the changes dictionary
#during iteration, the UpdateStones function tries to read the results of splitting
#if there are none, the stone is getting split up for the first time
#repeat for given steps
stones = {};
changes = {};
f = open("11.in","r");
for s in f.readline().strip().split(" "):
	si = int(s);
	if si not in stones: stones[si] = 0;
	stones[si] += 1;
f.close();

def SplitStones(stone):
	NewStones = [];
	if stone == 0:
		NewStones.append(1);
	elif len(str(stone))%2==0:
		stonestring = str(stone);
		sm = len(stonestring)//2;
		s1,s2 = stonestring[0:sm], stonestring[sm:];
		NewStones.append(int(s1));
		NewStones.append(int(s2));
	else:
		NewStones.append(stone*2024);
	return NewStones;

def UpdateStones(prevStones):
	Updated = {};
	for s in prevStones:
		if s not in changes: changes[s] = SplitStones(s);
		for c in changes[s]:
			if c not in Updated: Updated[c] = 0;
			Updated[c] += prevStones[s];
	return Updated;

steps1 = 25; #for part 1
steps2 = 75; #for part 2
for step in range(1,steps2+1):
	stones = UpdateStones(stones);
	if step == steps1: part1 = sum([stones[x] for x in stones]);
part2 = sum([stones[x] for x in stones]);
print("part 1 =", part1);
print("part 2 =", part2);