aoc 2025 1+2

2025/01/Findings.md

@@ -0,0 +1,13 @@
+# Day 01
+
+> First of all, what a joy not having 24 days, and no leaderboard. I actually really enjoy it and get more out of it. Turn off LLM, and just have fun 🤩
+
+## Part 1
+
+That was quite straight forward, nothing notable here. But it has been a while since I last used mod.
+
+## Part 2
+
+This was fun. So i wanted to (of course) not brute force it. Solution: first: calculate how many "empty" rounds the instruction had. e.g. `L106` would become simply `L6`) and simply increase by one. Now counting if we crossed `0` was interesting. I calculated the _distance to zero_ by checking how far the zero was, depending on the direction. And then simply seeing if the distance to travel was equally greater than the distance to zero.
+
+The gotcha which took me a few minutes, was that I was adding a zero to much, if I was starting at `0`. But the test data caught that as well!

2025/01/main.py

@@ -0,0 +1,49 @@
+def calc_1(lines):
+    position = 50
+    countZero = 0
+    for line in lines:
+        left = line[0] == "L"
+        distance = int(line[1:])
+        if left:
+            distance *= -1
+        position = (position + distance) % 100
+        if position == 0:
+            countZero += 1
+    return countZero
+
+
+# PART 2
+
+
+def calc_2(lines):
+    position = 50
+    countZero = 0
+    for line in lines:
+        left = line[0] == "L"
+        distance = int(line[1:])
+        rounds = abs(distance) // 100
+        countZero += rounds
+        distance = distance % 100
+        if left:
+            distance *= -1
+        distanceToZero = position if left else 100 - position
+        passesZero = abs(distance) >= distanceToZero
+        if passesZero and position != 0:
+            countZero += 1
+        position = (position + distance) % 100
+    return countZero
+
+
+def parse(raw: str):
+    return f.read().strip().splitlines()
+
+
+with open("./2025/01/train.txt") as f:
+    d = parse(f)
+    print(f"Train 1: {calc_1(d)}")
+    print(f"Train 2: {calc_2(d)}")
+
+with open("./2025/01/data.txt") as f:
+    d = parse(f)
+    print(f"Actual 1: {calc_1(d)}")
+    print(f"Actual 2: {calc_2(d)}")