Initial commit

2024/6/one.py

@@ -0,0 +1,47 @@
+#!/usr/bin/env python3
+
+import sys
+
+input_file = sys.argv[1]
+
+with open(input_file) as fd:
+    lines = [line.rstrip() for line in fd.readlines()]
+
+height = len(lines)
+width = len(lines[0])
+
+for i in range(height):
+    if "^" in lines[i]:
+        j = lines[i].index("^")
+        break
+
+d = 0
+directions = [
+    (-1, 0),  # ^
+    (0, 1),  # >
+    (1, 0),  # v
+    (0, -1),  # <
+]
+
+vis = [[False] * width for h in range(height)]
+
+while True:
+    print(i, j)
+    vis[i][j] = True
+    ii, jj = i + directions[d][0], j + directions[d][1]
+    if ii not in range(height) or jj not in range(width):
+        break
+    if lines[ii][jj] == "#":
+        d += 1
+        d %= len(directions)
+        continue
+    i, j = ii, jj
+
+count = 0
+for i in range(height):
+    for j in range(width):
+        if vis[i][j]:
+            count += 1
+print(count)
+
+

2024/6/two.py

@@ -0,0 +1,67 @@
+#!/usr/bin/env python3
+
+import sys
+
+input_file = sys.argv[1]
+
+with open(input_file) as fd:
+    lines = [line.rstrip() for line in fd.readlines()]
+
+height = len(lines)
+width = len(lines[0])
+
+for i_start in range(height):
+    if "^" in lines[i_start]:
+        j_start = lines[i_start].index("^")
+        break
+
+directions = [
+    (-1, 0),  # ^
+    (0, 1),  # >
+    (1, 0),  # v
+    (0, -1),  # <
+]
+
+positions: set[tuple[int, int]] = set()
+
+i, j = i_start, j_start
+d = 0
+
+while True:
+    positions.add((i, j))
+    ii, jj = i + directions[d][0], j + directions[d][1]
+    if ii not in range(height) or jj not in range(width):
+        break
+    if lines[ii][jj] == "#":
+        d += 1
+        d %= len(directions)
+        continue
+    i, j = ii, jj
+
+print(len(positions))
+positions.remove((i_start, j_start))
+
+tot = 0
+for obstacle in positions:
+    i, j = i_start, j_start
+    d = 0
+    path: set[tuple[int, int, int]] = set()
+
+    while True:
+        state = (i, j, d)
+        if state in path:
+            loop = True
+            tot += 1
+            break
+        path.add(state)
+        ii, jj = i + directions[d][0], j + directions[d][1]
+        if ii not in range(height) or jj not in range(width):
+            loop = False
+            break
+        if lines[ii][jj] == "#" or (ii, jj) == obstacle:
+            d += 1
+            d %= len(directions)
+            continue
+        i, j = ii, jj
+
+print(tot)