摘要：
You're given an array a1,…,ana1,…,an of nn non-negative integers. Let's call it sharpened if and only if there exists an integer 1≤k≤n1≤k≤n such that 阅读全文
摘要：
Let's define a number ebne (even but not even) if and only if its sum of digits is divisible by 22 but the number itself is not divisible by 22. For e 阅读全文