init

2023/day8/p2/main.py

@@ -0,0 +1,71 @@
+
+
+INPUT_FILE = "input.text"
+INSTRUCTIONS = []
+PATH = {}
+import math
+
+def read_file() -> None:
+    with open(INPUT_FILE, 'r') as file:
+        lines = file.readlines()
+
+    line_index = 0
+    for line in lines:
+
+        # This in our instruction line
+        if line_index == 0:
+            for char in line:
+                if char == 'L':
+                    INSTRUCTIONS.append(0)
+                elif char == 'R':
+                    INSTRUCTIONS.append(1)
+
+        elif line_index != 1:
+            source: str = line.split('=')[0].strip()
+
+            dest = line.split('=')[1].strip()[1:-1].split(', ')
+
+            PATH[source] = dest
+
+        line_index += 1
+
+def main() -> None:
+    read_file()
+
+    # print(PATH)
+
+    # Find all starting positions (because we're a ghost in the 4th dimension)
+    initial_positions = []
+    for pos in PATH:
+        if pos[2] == 'A':
+            initial_positions.append(pos)
+
+    # Find how many steps for each ghost to get to Z
+    steps_to_finish = []
+    for pos in initial_positions:
+
+        steps = 0
+        done = False
+        while True:
+
+            for instruction in INSTRUCTIONS:
+
+                pos = PATH[pos][instruction]
+
+                if pos[2] == 'Z':
+                    done = True
+                    break
+
+                steps += 1
+
+            if done:
+                steps_to_finish.append(steps + 1)
+                break
+
+    print(f'Steps to finish: {math.lcm(*steps_to_finish)}')
+
+
+
+
+if __name__ == "__main__":
+    main()