Problem G: Sequence Number

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Time Limit $1$ 秒/Second(s) Memory Limit $512$ 兆字节/Megabyte(s)
提交总数 $8$ 正确数量 $3$
裁判形式 标准裁判/Standard Judge 我的状态 尚未尝试
难度 分类标签

     In Linear algebra, we have learned the definition of inversion number:

    Assuming A is a ordered set with n numbers ( n > 1 ) which are different from each other. If exist positive integers i , j, ( 1 ≤ i < j ≤ n and A[i] > A[j]), <A[i], A[j]> is regarded as one of A’s inversions. The number of inversions is regarded as inversion number. Such as, inversions of array <2,3,8,6,1> are <2,1>, <3,1>, <8,1>, <8,6>, <6,1>,and the inversion number is 5.

     Similarly, we define a new notion —— sequence number, If exist positive integers i, j, ( 1 ≤ i ≤ j ≤ n and A[i]  <=  A[j], <A[i], A[j]> is regarded as one of A’s sequence pair. The number of sequence pairs is regarded as sequence number. Define j – i as the length of the sequence pair.

     Now, we wonder that the largest length S of all sequence pairs for a given array A. 

    There are multiply test cases.

    In each case, the first line is a number N(1<=N<=50000 ), indicates the size of the array, the 2th ~n+1th line are one number per line, indicates the element Ai (1<=Ai<=10^9) of the array.  

 Output the answer S in one line for each case. 

5
2 3 8 6 1
3