Minimum AND xor OR
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## 1-D Array, Arrays, Data Structures, Operators, Sorting

Problem
Editorial
Analytics

You are given an array $A$ of $N$ integers. Determine the minimum value of the following expression for all valid $i,j$:

$(A_i \ and \ A_j) \ xor \ (A_i \ or \ A_j)$, where $i \ne j$.

Input format

• First line: A single integer $T$ denoting the number of test cases
• For each test case:
• First line contains a single integer $N$, denoting the size of the array
• Second line contains $N$ space-separated integers $A_1,A_2,...,A_n$

Output format

For each test case, print a single line containing one integer that represents the minimum value of the given expression

Constraints

$1 \le T \le 10^3\\ 1 \le N \le 10^5\\ 0 \le A_i \le 10^9$

Note: Sum of $N$ overall test cases does not exceed $10^6$

SAMPLE INPUT
2
5
1 2 3 4 5
3
2 4 7


SAMPLE OUTPUT
1
3


Explanation

For test case #1, we can select elements $2$ and $3$, the value of the expression is $(2 \ and \ 3) \ xor \ (2 \ or \ 3) = 1$, which is the minimum possible value. Another possible pair is 4 and 5.

For test case #2, we can select elements 4 and 7, the value of the expression is $(4 \ and \ 7) \ xor \ (4 \ or \ 7) = 3$, which is the minimum possible value.

Time Limit: 1.0 sec(s) for each input file.
Memory Limit: 256 MB
Source Limit: 1024 KB

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