摘要：C. Table Compression Little Petya is now fond of data compression algorithms. He has already studied gz, bz, zip algorithms and many others. Inspired 阅读全文

摘要：Watchmen 题意:有n (1 ≤ n ≤ 200 000) 个点，问有多少个点的开平方距离与横纵坐标的绝对值之差的和相等； 即 = |xi - xj| + |yi - yj|.(|xi|, |yi| ≤ 109) 思路:开始想的是容斥原理，即按x,y分别排序，先计算同x的点，然后在计算同y的点 阅读全文

摘要：Vasya's telephone contains n photos. Photo number 1 is currently opened on the phone. It is allowed to move left and right to the adjacent photo by sw 阅读全文