python: ex2: add solution

python/ex2.py

@@ -0,0 +1,25 @@
+#!/usr/bin/env python
+
+from copy import copy
+
+
+def f(n: int) -> list[list[int]]:
+    if n == 0:
+        return []
+    if n == 1:
+        return [[1]]
+
+    res = f(n - 1)
+    res.append(copy(res[-1]))
+    res[-1].append(n)
+
+    return res
+
+
+def main():
+    for i in range(5):
+        print(f"f({i})={f(i)}")
+
+
+if __name__ == "__main__":
+    main()