2023 dec 10th

Python/2023/10/main.py

@@ -0,0 +1,101 @@
+import math
+
+input = open("input", 'r')
+
+data = []
+start = (0,0)
+
+for i, line in enumerate(input):
+    line = line.rstrip()
+    if "S" in line:
+        for j in range(len(line)):
+            if line[j] == "S":
+                start = (i, j)
+    data.append(list(line))
+
+# replace "S" with character based on input so I don't need a bunch of code for it. line[j] = "7"
+data[start[0]][start[1]] = "7"
+# data[start[0]][start[1]] = "F"
+
+explored = [["." for _ in line] for line in data]
+
+def north(pos):
+    return ((pos[0]-1, pos[1]), "s")
+def south(pos):
+    return ((pos[0]+1, pos[1]), "n")
+def east(pos):
+    return ((pos[0], pos[1]+1), "w")
+def west(pos):
+    return ((pos[0], pos[1]-1), "e")
+
+def next_tile(pos, prev_card):
+    tile = data[pos[0]][pos[1]]
+    explored[pos[0]][pos[1]] = tile
+    if tile == "|":
+        return north(pos) if prev_card == "s" else south(pos)
+    if tile == "L":
+        return north(pos) if prev_card == "e" else east(pos)
+    if tile == "J":
+        return north(pos) if prev_card == "w" else west(pos)
+    if tile == "F":
+        return south(pos) if prev_card == "e" else east(pos)
+    if tile == "7":
+        return south(pos) if prev_card == "w" else west(pos)
+    if tile == "-":
+        return east(pos) if prev_card == "w" else west(pos)
+    print("ERROR")
+    return (pos, prev_card)
+
+forward = next_tile(start, "w")
+backward = next_tile(start, "s")
+
+iters = 1
+while forward[0] != backward[0]:
+    forward = next_tile(*forward)
+    backward = next_tile(*backward)
+    iters += 1
+
+print(iters)
+
+insides = 0
+
+# for row in explored:
+#     for column in row:
+#         print(column, end=" ")
+#     print()
+
+for i, row in enumerate(explored):
+    pipes_crossed = 0
+    j = 0
+    while j < len(row):
+        start_j = j
+        tile = row[j]
+        if tile == "." and pipes_crossed % 2 == 1:
+            explored[i][j] = "I"
+            insides += 1
+        elif tile == "|":
+            pipes_crossed += 1
+        elif tile == "L":
+            j += 1
+            tile = row[j]
+            while tile == "-":
+                j += 1
+                tile = row[j]
+            if tile == "7":
+                pipes_crossed += 1
+        elif tile == "F":
+            j += 1
+            tile = row[j]
+            while tile == "-":
+                j += 1
+                tile = row[j]
+            if tile == "J":
+                pipes_crossed += 1
+        j += 1
+
+# for row in explored:
+#     for column in row:
+#         print(column, end="")
+#     print()
+
+print(insides)