Writer: jjjjj19980806 Description: pclightyear Difficulty: ★★★☆☆
Given n numbers, you need to find a number k such that SUM is minimum,
where we define SUM = ( a1 ^ k ) + ( a2 ^ k ) + ... + ( an ^ k )
(^ stands for the "xor" bitwise operation of the two operand)
The first line contains an integer n, representing the number of numbers.
The next line contains n integers ai, representing each given number.
It is guaranteed that:
Please output the value of SUM.
Note SUM may exceed INT.