2016: d09: ex2: add solution

2016/d09/ex2/ex2.py

@@ -0,0 +1,39 @@
+#!/usr/bin/env python
+
+import sys
+from collections.abc import Iterator
+
+
+def solve(input: str) -> int:
+    def decompress(input: str) -> int:
+        def helper() -> Iterator[int]:
+            i = 0
+            is_marker = False
+            while i < len(input):
+                if is_marker:
+                    j = input.find(")", i)
+                else:
+                    j = input.find("(", i)
+                if j == -1:
+                    j = len(input)
+                if is_marker:
+                    length, repeat = map(int, input[i + 1 : j].split("x"))
+                    yield decompress(input[j + 1 : j + length + 1]) * repeat
+                    i = j + length + 1
+                else:
+                    yield j - i
+                    i = j
+                is_marker = not is_marker
+
+        return sum(helper())
+
+    return decompress(input.strip())
+
+
+def main() -> None:
+    input = sys.stdin.read()
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()