Solve day 21 and 22 2017.

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()