USACO 2022 US Open Contest, Platinum Problem 3. Up Down Subsequence
USACO 2022 US Open Contest, Platinum Problem 3. Up Down Subsequence Farmer John's?NN?cows (2≤N≤3?1052≤N≤3?105), conveniently numbered?1…N1…N?as usual, have ordered themselves according to a permuta...