2025(06): thanks to loops, things work

2.28 ms ± 347 μs per loop (mean ± std. dev. of 7 runs, 100 loops each)

2025/06/part2.py

@@ -0,0 +1,68 @@
+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())
+    
+    	# For the last column, I don't have that nice column of nothing
+		if icol == num_of_cols - 1:
+			col_len += 1
+
+		# Prepare empty string for my numbers
+		nums = (col_len - 1)*[""]
+
+		# Make the num strings by moving row by row
+		for jcol in range(icol_prev, icol_prev + col_len - 1):
+			for row in data[:-1]:
+				nums[jcol - icol_prev] += row[jcol]
+
+		# Do the math
+		if op == '*':
+			result = 1
+			if debug:
+				print(1, end="")
+			for num in nums:
+				num = int(num)
+				if debug:
+					print(f" * {num}", end="")
+
+				result *= num
+		elif op == '+':
+			result = 0
+			if debug:
+				print(0, end="")
+			for num in nums:
+				num = int(num)
+				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") == 3263827
+
+	print(do_homework("input"))