Given an array of 0's and 1's your task is to complete the function **maxLen** which returns size of the largest sub array with equal number of 0's and 1's .

The function** maxLen** takes 2 arguments .The first argument is the array **A[]** and second argument is the size** 'N'** of the array **A[] **.

**Input:**

The first line of the input is** T** denoting the number of test cases .

Then **T** test cases follow . Each test case contains two lines .

The first line of each test case is a number **N** denoting the size of the array and in the next line are **N** space separated values of **A [ ]**.

**Output:**

For each test case output in a new line the max length of the subarray .

**Constraints:**

1<=T<=100

1<=N<=100

0<=A[ ] <=1

**Example:
Input (To be used only for expected output) :**

2

4

0 1 0 1

5

0 0 1 0 0

4

2