1543 - A simple problem

Time Limit : 2 Second

Memory Limit : 128 MB

Submission: 155

Solved: 8

Description
Given a permutation P of 1 to N, YY wants to know whether there exists such three elements P[i1], P[i2], P[i3] that P[i1]-P[i2]=P[i2]-P[i3], 1<=i1<i2<i3<=N.

Input
The first line is T(T<=60), representing the total test cases.

Each test case comes two lines, the former one is N, 3<=N<=10000, the latter is a permutation of 1 to N.

Output
For each test case, just output 'Y' if such i1, i2, i3 can be found, else 'N'.

sample input
2
3
1 3 2
4
3 2 4 1
sample output
N
Y
hint
source
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