Solve day 21 and 22 2017.

2017/d21.py

@@ -0,0 +1,110 @@
+IMAGE = """.#.
+..#
+###"""
+
+
+def flipv(pattern):
+    return tuple(map(lambda row: tuple(reversed(row)), pattern))
+    
+
+def fliph(pattern):
+    return tuple(reversed(pattern))
+
+
+def rot90(pattern):
+    return tuple(map(tuple, map(reversed, tuple(zip(*pattern)))))
+
+
+def parse_rule(line: str) -> dict:
+    lhs, rhs = line.split(" => ")
+    rules = {}
+    lhs = tuple(map(tuple, lhs.split("/")))
+    rhs = list(map(list, rhs.split("/")))
+
+    rules[lhs] = rhs
+
+    rules[rot90(lhs)] = rhs
+    rules[rot90(rot90((lhs)))] = rhs
+    rules[rot90(rot90(rot90((lhs))))] = rhs
+
+    rules[flipv(lhs)] = rhs
+    rules[fliph(lhs)] = rhs
+
+    rules[rot90(flipv(lhs))] = rhs
+    rules[rot90(rot90(flipv(lhs)))] = rhs
+    rules[rot90(rot90(rot90(flipv(lhs))))] = rhs
+
+    rules[rot90(fliph(lhs))] = rhs
+    rules[rot90(rot90(fliph(lhs)))] = rhs
+    rules[rot90(rot90(rot90(fliph(lhs))))] = rhs
+
+    return rules
+
+
+def print_image(image):
+    for row in image:
+        print("".join(row))
+
+
+def slice_get(matrix, row, col, size):
+    r = []
+    for ri in range(row, row + size):
+        r.append(matrix[ri][col:col+size])
+    return r
+
+
+def slice_set(matrix, row, col, new):
+    for ri, r in enumerate(new):
+        matrix[ri + row][col:col + len(r)] = r
+
+
+def slice_append(matrix, slice):
+    for ri, row in enumerate(slice):
+        for c in row:
+            matrix[-len(slice) + ri].append(c)
+
+
+def part_1(data, iterations=5):
+    rules = {}
+    image = list(map(list, IMAGE.splitlines()))
+    for line in data.splitlines():
+        line = line.strip()
+        for k, v in parse_rule(line).items():
+            assert (k not in rules) or rules[k] == v
+            rules[k] = v
+
+    for _ in range(iterations):
+        len_image = len(image)
+        new_image = []
+        if len_image % 2 == 0:
+            for row in range(0, len(image), 2):
+                for _ in range(3):
+                    new_image.append([])
+                for col in range(0, len(image[0]), 2):
+                    slice = tuple(map(tuple, slice_get(image, row, col, 2)))
+                    new_slice = rules[slice]
+                    slice_append(new_image, new_slice)
+        else:
+            for row in range(0, len(image), 3):
+                for _ in range(4):
+                    new_image.append([])
+                for col in range(0, len(image[0]), 3):
+                    slice = tuple(map(tuple, slice_get(image, row, col, 3)))
+                    new_slice = rules[slice]
+                    slice_append(new_image, new_slice)
+        image = new_image
+
+    count = 0
+    for row in image:
+        count += row.count("#")
+    print(count)
+
+
+def main():
+    data = open(0).read()
+    part_1(data)
+    part_1(data, 18)
+
+
+if __name__ == "__main__":
+    main()

2017/d22.py

@@ -0,0 +1,71 @@
+from lib import Grid2D, add2
+
+
+def part_1(data):
+    steps = 10_000
+
+    g = Grid2D(data)
+    # g.print()
+    dirs = [g.N, g.E, g.S, g.W]
+
+    pos = (g.n_rows // 2, g.n_cols // 2)
+    dir = g.N
+
+    inf = set(g.find("#"))
+
+    burst_inf = 0
+    for _ in range(steps):
+        if pos in inf:
+            # turn right
+            dir = dirs[(dirs.index(dir) + 1) % len(dirs)]
+            inf.remove(pos)
+        else:
+            # turn left
+            dir = dirs[(dirs.index(dir) - 1) % len(dirs)]
+            inf.add(pos)
+            burst_inf += 1
+        pos = add2(pos, dir)
+    print(burst_inf)
+
+
+def part_2(data):
+    steps = 10000000
+
+    g = Grid2D(data)
+    dirs = [g.N, g.E, g.S, g.W]
+
+    pos = (g.n_rows // 2, g.n_cols // 2)
+    dir = g.N
+
+    weak = set()
+    inf = set(g.find("#"))
+    flagged = set()
+
+    burst_inf = 0
+    for _ in range(steps):
+        if pos in weak:
+            weak.remove(pos)
+            inf.add(pos)
+            burst_inf += 1
+        elif pos in inf:
+            dir = dirs[(dirs.index(dir) + 1) % len(dirs)]
+            inf.remove(pos)
+            flagged.add(pos)
+        elif pos in flagged:
+            dir = dirs[(dirs.index(dir) + 2) % len(dirs)]
+            flagged.remove(pos)
+        else:
+            dir = dirs[(dirs.index(dir) - 1) % len(dirs)]
+            weak.add(pos)
+        pos = add2(pos, dir)
+    print(burst_inf)
+
+
+def main():
+    data = open(0).read()
+    part_1(data)
+    part_2(data)
+
+
+if __name__ == "__main__":
+    main()

README.md

@@ -81,4 +81,6 @@ written in Python.
 - Day 18: 23:00
 - Day 19: 45:00
 - Day 20: 9:55 (would have been 10th)
-- Day 21:
+- Day 21: 90:00
+- Day 22: 25:00
+- Day 23: