2025(06): solve part 1 without dependencies

2025/06/part1.py

@@ -0,0 +1,56 @@
+debug = False
+
+def do_homework(filename: str):
+	# Read file as list of strings
+	with open(filename, "r") as fp:
+		data = fp.read().splitlines()
+
+	# Gimme the operators
+	last_row = data[-1]
+	operators = last_row.split()
+
+	# Use that to find the lengths
+	num_of_cols = len(operators)
+
+	icol_prev = 0
+	final_result = 0
+	for icol in range(num_of_cols):
+		op = operators[icol]
+
+		# Find the length of this column.
+		col_len = len(last_row[icol_prev:]) - len(last_row[icol_prev + 1:].lstrip())
+		
+		# Do the math
+		if op == '*':
+			result = 1
+			if debug:
+				print(1, end="")
+			for row in data[:-1]:
+				num = int(row[icol_prev:icol_prev + col_len])
+				if debug:
+					print(f" * {num}", end="")
+
+				result *= num
+		elif op == '+':
+			result = 0
+			if debug:
+				print(0, end="")
+			for row in data[:-1]:
+				num = int(row[icol_prev:icol_prev + col_len])
+				if debug:
+					print(f" + {num}", end="")
+
+				result += num
+		else:
+			assert False, "fuck this"
+		
+		icol_prev += col_len
+		final_result += result
+		if debug:
+			print(f" = {result}")
+	return final_result
+
+if __name__ == "__main__":
+	assert do_homework("testinput") == 4277556
+
+	print(do_homework("input"))