#advent of code 2024
#day 09 - part 1
#I'll rewrite it to include both parts in the same file one day
#tbh I'm not even reviewing this shit
#very slow part 1, part 2 relatively fast

part1 = 0;
disk = open("09.in","r").readline().strip();
files = {};
freespace = {};
NewDisk = {};
fid = 0;
sid = 0;
ind = 0;
for i in range (0,len(disk)):
	if i%2 == 0:
		files[fid] =[int(x)+ind for x in range(int(disk[i]))];
		ind += int(disk[i]);
		fid += 1;
	else:
		freespace[sid] = [int(x)+ind for x in range(int(disk[i]))];
		ind += int(disk[i]);
		sid +=1;

si = 0; #space index
fi = fid -1; #file index
originalSize = len(files[fi]);
while sum([len(freespace[x]) for x in freespace]) > 0:
	#empty list of freespaces - change to another one
	if len(freespace[si]) == 0: 
		si += 1;
		continue;
		
	#clear freespace that is after the fileblock with biggest index
	FileMax = max([max(files[x]) for x in files]);
	if FileMax < freespace[si][-1]: 
		freespace[si].pop(-1); 
		continue; 
	
	#switch places between last fileblock and first freespace
	files[fi].pop(); 
	originalSize -= 1;
	NewSpace = freespace[si].pop(0);
	files[fi].insert(0,NewSpace);
	
	#if that was the last fileblock, switch to second to last file
	if originalSize == 0:
		fi -= 1;
		originalSize = len(files[fi]);

#checksum calculation
for file in files:
	for f in files[file]:
		part1 += file*f;

print("part 1 =", part1);