摘要：
Consider a multiset of integers S, the union of n closed intervals of positive integers: S = [l1..r1] ∪ [l2..r2] ∪ · · · ∪ [ln..rn](recall that a clos 阅读全文
摘要：
Smaller input size: https://codeforces.com/contest/1249/problem/D1 Big input size: https://codeforces.com/contest/1249/problem/D2 Given n segments on 阅读全文
摘要：
You are given a string consisting of the letters x and y, such as xyxxxyxyy. In addition, you have an operation called flip, which changes a single x 阅读全文