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CF1454B.Unique Bid Auction
Unique Bid Auction
There is a game called "Unique Bid Auction". You can read more about it here: https://en.wikipedia.org/wiki/Unique\_bid\_auction (though you don't have to do it to solve this problem).
Let's simplify this game a bit. Formally, there are participants, the -th participant chose the number . The winner of the game is such a participant that the number he chose is unique (i. e. nobody else chose this number except him) and is minimal (i. e. among all unique values of the minimum one is the winning one).
Your task is to find the index of the participant who won the game (or -1 if there is no winner). Indexing is -based, i. e. the participants are numbered from to .
You have to answer independent test cases.
Input
The first line of the input contains one integer () — the number of test cases. Then test cases follow.
The first line of the test case contains one integer () — the number of participants. The second line of the test case contains integers (), where is the -th participant chosen number.
It is guaranteed that the sum of does not exceed ().
Output
For each test case, print the answer — the index of the participant who won the game (or -1 if there is no winner). Note that the answer is always unique.
Samples
6
2
1 1
3
2 1 3
4
2 2 2 3
1
1
5
2 3 2 4 2
6
1 1 5 5 4 4
-1
2
4
1
2
-1
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