XOr

시간 제한1초메모리 제한1024 MB

요약

수열을 정확히 m개의 연속한 부분으로 나눌 때, 각 부분의 XOR 합들을 모두 OR한 값이 최소가 되도록 한다.

문제

bobo has a sequence of integers $a\_1, a\_2, \dots, a\_n$ . He decides to divide the sequence into exactly $m$ consecutive parts.

The cost of each part is its xor sum (bitwise exclusive-or), while the cost of division is bitwise or-sum of its parts' costs.

Help bobo find the minimum cost.

The first line contains $2$ integers $n, m$ ( $1 \leq n \leq 200000, 1 \leq m \leq n$ ).

The second line contains $n$ integers $a\_1, a\_2, \dots, a\_n$ ( $0 \leq a\_i \leq 10^9$ ).

A single integer denotes the minimum cost.