Submission #47514980

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Source Code Expand

use proconio::input;

fn main() {
    input! {
        n: usize,
    }
    let n = 2 * n;
    let a = (0..n)
        .map(|i| {
            input! { a: [u64; n - 1 - i] }
            a
        })
        .collect::<Vec<_>>();
    let mut ans = 0;
    let mut p = (0..n).collect::<Vec<_>>();
    while {
        let mut score = 0;
        for p in p.chunks_exact(2) {
            score ^= a[p[0]][p[1] - p[0] - 1];
        }
        ans = ans.max(score);
        next_pairing(&mut p)
    } {}
    println!("{}", ans);
}

pub fn next_pairing(p: &mut [usize]) -> bool {
    let n = p.len();
    let mut used = 0_u32;
    for i in (0..n).rev() {
        used |= 1 << p[i];
        if i % 2 == 1 && p[i] < used.ilog2() as usize {
            p[i] = (used >> (p[i] + 1)).trailing_zeros() as usize + p[i] + 1;
            used ^= 1 << p[i];
            for i in i + 1..n {
                p[i] = used.trailing_zeros() as usize;
                used ^= 1 << p[i];
            }
            return true;
        }
    }
    false
}

Submission Info

Judge Result