摘要：题目链接 题目 Peter decided to wish happy birthday to his friend from Australia and send him a card. To make his present more mysterious, he decided to make 阅读全文

摘要：题目链接 题目 Your company has just constructed a new skyscraper, but you just noticed a terrible problem: there is only space to put one game room on each 阅读全文

摘要：题目链接 首先第一问很好求，就是求最长下降子序列，\(n\leqslant 5000\)，\(O(n^2)\) 暴力转移就行。 而这道题的难点就在于去重。 对于 \(i\) 和 \(j\)（\(i>j\)），如果 \(a_i=a_j\) 且 \(dp_i=dp_j\)，说明他们是相同的，\(i\) 阅读全文

摘要：题目大意 我们称一个集合 \(S={(x_1, y_1), (x_2, y_2), … , (x_k, y_k)}\) 是好的，当且仅当把它们按照 \(y_i\) 降序排序后满足： 对于所有满足 \(3 ≤ j ≤ k\) 的 \(j\)，有 \(x_j−2 < x_j < x_j−1\) 或者 \ 阅读全文