run_length.rs

//! ランレングス
pub fn compress(s: &str) -> Vec<(char, usize)> {
    let vs = s.chars().collect::<Vec<_>>();

    let mut buff = vs[0];
    let mut count = 1;
    let mut v = vec![];
    for c in vs.iter().skip(1) {
        if *c != buff {
            v.push((buff, count));
            count = 1;
            buff = *c;
        } else {
            count += 1;
        }
    }
    v.push((buff, count));
    v
}

#[cfg(test)]
mod tests {
    use super::*;
    #[test]
    fn test_run_length() {
        let v = vec![('a', 5usize), ('b', 3), ('c', 1)];

        assert_eq!(compress("aaaaabbbc"), v);
    }
}