HDU6592 Beauty Of Unimodal Sequence

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HDU6592 Beauty Of Unimodal Sequence

Beauty Of Unimodal Sequence 给一个序列,在满足单调递增或者单调递减或者先增后减的最长子序列集合里找到下标字典序最大以及最小的两个子序列,输出这两个子序列里元素的下标. n≤3×105 moomhxy的题解先正着求一遍LIS,再反着求一遍LIS,求出每个点作为上升子序列结尾的最大长度和每个点作为下降子序列开头的最大长度. 我们可以枚举这个单峰序列的峰顶是什么,这样最长长度就找到了. 然后考虑怎么构造解. 求字典序最小的话,首先找到第一个顶峰,然后往前找递减的序列中下标…

2019年杭电多校第二场 1002题Beauty Of Unimodal Sequence(LIS+单调栈)

题目链接传送门思路首先我们对\(a\)正反各跑一边\(LIS\),记录每个位置在前一半的\(LIS\)中应该放的位置\(ans1[i]\),后一半的位置\(ans2[i]\). 对于字典序最小的方案,我们找到第一个峰值,然后往前遍历.在\(i\)这个位置,如果它在\(LIS\)中放的位置是\(pos\),那么我们先看当前放在\(pos+1\)的值是否比它大,大的话就说明这个位置一定比前面放过在\(pos\)这个位置的更优(因为字典序更小,且\([1,i]\)一定可以放满\([1,pos-1…

2019DX#2

Solved Pro.ID Title Ratio(Accepted / Submitted) 1001 Another Chess Problem 8.33%(1/12) 1002 Beauty Of Unimodal Sequence 19.07%(74/388) 1003 Coefficient 6.76%(5/74) 1004 Double Tree 0.00%(0/20) 1005 Everything Is Generated In Equal Probabili…

2019 Multi-University Training Contest 2

2019 Multi-University Training Contest 2 A. Another Chess Problem B. Beauty Of Unimodal Sequence 题意给一个序列,求下标字典序最小和字典序最大的,先增后减的序列. 解体过程比赛时首先不知道字典序最小LIS怎么求. 试图枚举分界点.[解体的开始] 公无渡河,公竟渡河? 活鱼在摸鱼,rdc在划水,sdcgvhgj在水深火热. 做法考虑字典序最小的LIS怎么求? 这是个经典问题,预处理前缀LIS后缀L…

hdu-5496 Beauty of Sequence(递推)

题目链接: Beauty of Sequence Time Limit: 6000/3000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 813 Accepted Submission(s): 379 Problem Description Sequence is beautiful and the beauty of an integer sequence is def…

HDU 5496 Beauty of Sequence

题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=5496 Beauty of Sequence Problem Description Sequence is beautiful and the beauty of an integer sequence is defined as follows: removes all but the first element from every consecutive group of equivalen…