C. Tenzing and Balls
dp
Enjoy erasing Tenzing, identified as Accepted!Tenzing has \(n\) balls arranged in a line. The color of the \(i\)-th ball from the left is \(a_i\).Tenzing can do the following operation any number of times: select \(i\) and \(j\) such that \(1\leq i < j \leq |a|\) and \(a_i=a_j\), remove \(a_i,a_{i+1},\ldots,a_j\) from the array (and decrease the indices of all elements to the right of \(a_j\) by \(j-i+1\)). Tenzing wants to know the maximum number of balls he can remove.
Each test contains multiple test cases. The first line of input contains a single integer \(t\) (\(1\leq t\leq 10^3\)) — the number of test cases. The description of test cases follows.The first line contains a single integer \(n\) (\(1\leq n\leq 2\cdot 10^5\)) — the number of balls.The second line contains \(n\) integers \(a_1,a_2,\ldots,a_n\) (\(1\leq a_i \leq n\)) — the color of the balls.It is guaranteed that sum of \(n\) of all test cases will not exceed \(2\cdot 10^5\).
For each test case, output the maximum number of balls Tenzing can remove.
In the first example, Tenzing will choose \(i=2\) and \(j=3\) in the first operation so that \(a=[1,3,3]\). Then Tenzing will choose \(i=2\) and \(j=3\) again in the second operation so that \(a=[1]\). So Tenzing can remove \(4\) balls in total.In the second example, Tenzing will choose \(i=1\) and \(j=3\) in the first and only operation so that \(a=[2]\). So Tenzing can remove \(3\) balls in total.