use std::cmp::Ordering::*;

pub fn binary_search<T: Ord>(data: &[T], target: &T) -> Option<usize> {
    let mut high = data.len();
    let mut low = 0;
    let mut mid = high / 2;

    while low < high {
        match target.cmp(&data[mid]) {
            Less => high = mid - 1,
            Greater => low = mid + 1,
            Equal => return Some(mid),
        };
        mid = (high + low) / 2;
    }
    None
}