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+#advent of code 2020
+#day 08
+#a little bit bruteforce-ish, 
+#for part 2 I mark instruction that are actually used by boot code
+#then I loop over the marked instructions and replace them 1 by 1 until 
+#the infinite cycle is broken
+#also the input kept getting broken and needed to change the parsing
+#which isn't a hard bug, but an annoying one
+#ALSO during rewriting I figured out that I don't need to calculate 
+#part 1 separately, it's already used during cycle detection
+#although this might just be a coincidence; honestly I'm not confident
+#in cycle detection puzzles
+
+BootCode = []
+PuzzleInput = open("08.in","r")
+for x in PuzzleInput:
+	if len(x) == 0: continue; #please ignore it, I'm bad at parsing
+	instr, val = x.split(" ");
+	BootCode.append(x.replace("\n",""));
+PuzzleInput.close();
+
+index = 0;
+accumulator = 0;
+visited = set();
+#the "Im sure it works" method for part 1
+while True:
+	instr, val = BootCode[index].split(" ");
+	#order += 1;
+	if index in visited: break;
+	visited.add(index);
+	if instr == "nop": 
+		index += 1;
+	elif instr == "acc":
+		accumulator += int(val);
+		index += 1;
+	elif instr == "jmp": 
+		index += int(val);
+
+print("part 1 =",accumulator);
+
+index = 0;
+accumulator = 0;
+accVals = dict();
+p1 = None;
+#the "it works for me but might be luck" method for part 1
+while index <= len(BootCode):
+	instr, val = BootCode[index].split(" ");
+	Current, Previous = accVals.get(index,(None,None));
+	if Previous and Current and Previous%accumulator == Previous%accumulator:
+		p1 = Current;
+		break;
+	accVals[index] = (accumulator, Current);
+	if instr == "nop": 
+		index += 1;
+	elif instr == "acc":
+		accumulator += int(val);
+		index += 1;
+	elif instr == "jmp": 
+		index += int(val);
+
+print("part 1 =",p1);
+
+p2 = None;
+for i in accVals:
+	if BootCode[i].split(" ")[0] == "acc": continue;
+	index = 0;
+	accumulator = 0;
+	accValsNested = dict();
+	NoCycle = True;
+	while index < len(BootCode):
+		instr, val = BootCode[index].split(" ");
+		Current, Previous = accValsNested.get(index,(None,None));
+		if Previous and Current and Previous%accumulator == Previous%accumulator:
+			NoCycle = False;
+			break;
+		accValsNested[index] = (accumulator, Current);
+		if index == i: #swap instructions
+			if instr == "nop": 
+				instr = "jmp";
+			elif instr == "jmp":
+				instr = "nop";
+		if instr == "nop": 
+			index += 1;
+		elif instr == "acc":
+			accumulator += int(val);
+			index += 1;
+		elif instr == "jmp": 
+			index += int(val);
+	if NoCycle:
+		p2 = accumulator;
+		break;
+
+print("part 2 =", p2);