Simple quicksort in rust

qsort.rs

fn qs(a: &mut [i32]) {
    if a.len() <= 1 { return; }

    // track index of the first element that >= pivot (last element)
    // gte = greater than or equal
    let mut first_gte_index = 0;
    let pivot_index = a.len() - 1;
    for i in 0..pivot_index {
        if a[i] >= a[pivot_index] { continue; }
        a.swap(i, first_gte_index);
        first_gte_index += 1;
    }
    a.swap(first_gte_index, pivot_index);

    qs(&mut a[0..first_gte_index]);
    qs(&mut a[(first_gte_index + 1)..(pivot_index + 1)]);
}

fn main() {
    let mut a = [-1,0,-2,5,7,0,-6,1];
    qs(&mut a);
    println!("{:?}", a);
}