2018-12-31から1日間の記事一覧
https://codeforces.com/contest/1091/problem/DThe sum is N(N+1)/2 is equivalent to the sequence is a permutation. For N=10, we have two permutations AAAABBBBBB CCCCDDDDDDWhen BBBBBBCCCC is a permutation, BBBBBB is not sorted in descending o…