Solve 2015 days 11-18.

2015/d18.py

@@ -0,0 +1,40 @@
+data = open(0).read().strip()
+
+part_2 = False
+rows = list(map(str, data.splitlines()))
+nrows = len(rows)
+ncols = len(rows[0])
+
+for _ in range(100):
+    new_field = []
+    for r in range(nrows):
+        nrow = []
+        for c in range(ncols):
+            count = 0
+            for nb in [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]:
+                nr = r + nb[0]
+                nc = c + nb[1]
+                if nr < 0 or nr >= nrows or nc < 0 or nc >= ncols:
+                    continue
+                if rows[nr][nc] == "#":
+                    count += 1
+            if rows[r][c] == "#" and (count == 2 or count == 3):
+                nrow.append("#")
+            elif rows[r][c] == "." and count == 3:
+                nrow.append("#")
+            else:
+                nrow.append(".")
+        new_field.append(nrow)
+    rows = new_field
+    if part_2:
+        rows[0][0] = "#"
+        rows[0][ncols - 1] = "#"
+        rows[nrows - 1][0] = "#"
+        rows[nrows - 1][ncols - 1] = "#"
+
+r = 0
+for row in rows:
+    for c in row:
+        if c == "#":
+            r += 1
+print(r)