Function shuffle

src/common/util.rs:4–7

(data: &mut [T])

use rand::prelude::SliceRandom;

pub fn shuffle<T>(data: &mut [T]) {
    let mut rng = rand::thread_rng();
    data.shuffle(&mut rng);
}

// n, item length
// n = 1, vec!["a", "b", ... "z"]