Codeforces Round #596 (Div. 2, based on Technocup 2020 Elimination Round 2)D - Power Products
D.PowerProductstimelimitpertest2secondsmemorylimitpertest512megabytesinputstandardinputoutputstandardoutputYouaregivennnpositiveintegersa1,…,ana1,…,an,andanintegerk≥2k