Function sort_dth

src/sort/insert.rs:25–37

insertion sort a[lo..=hi], starting at d-th character lo & hi, is inclusive

(a: &mut [T], lo: usize, hi: usize, d: usize)

/// insertion sort a[lo..=hi], starting at d-th character
/// lo & hi, is inclusive
pub fn sort_dth<T>(a: &mut [T], lo: usize, hi: usize, d: usize)
where
    T: AsRef<str>,
{
    // i begin with `lo + 1`
    for i in lo + 1..=hi {
        let mut j = i;
        while j > lo && is_less(a[j].as_ref(), a[j - 1].as_ref(), d) {
            a.swap(j, j - 1);
            j -= 1;
        }
    }
}

/// is v less than w, starting at d-th character
fn is_less(v: &str, w: &str, d: usize) -> bool {