You are given a string of 2N characters consisting of N ‘[‘ brackets and N ‘]’ brackets. A string is considered balanced if it can be represented in the for S2[S1] where S1 and S2 are balanced strings. We can make an unbalanced string balanced by swapping adjacent characters. Calculate the minimum number of swaps necessary to make a string balanced.
The first line of input contains an integer T denoting the number of test cases. Then T test cases follow. The first line of each test case contains an integer N denoting the length of the string.
The second line of each test case contains the string consisting of '[' and ']'.
Print the minimum number of swaps to make the string balanced for each test case in a new line.
1<= T <=100
1<= N <=100000
Input : ][ Output : 2 First swap: Position 3 and 4 ][ Second swap: Position 5 and 6  Input : [] Output : 0 String is already balanced.
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