摘要：
You are given a sequence a1,a2,…,an consisting of n integers. You can choose any non negative integer D (i.e. D≥0), and for each ai you can: add D (on 阅读全文
摘要：
Polycarp has guessed three positive integers a, b and c. He keeps these numbers in secret, but he writes down four numbers on a board in arbitrary ord 阅读全文