use std::collections::HashMap;

pub fn task_scheduler(tasks: &[char], coldown: u8) -> u16 {
    let mut num_tasks = HashMap::new();
    for task in tasks {
        *num_tasks.entry(task).or_insert(0) += 1;
    }

    let mut num_tasks: Vec<(&&char, &i32)> = num_tasks.iter().collect();
    num_tasks.sort_by(|a, b| b.1.cmp(a.1));

    let mut result = 0;
    let mut pos = 0;
    let mut range = 1;

    for _ in 0..tasks.len() {
        if num_tasks.get(pos as usize).is_none() {
            result += if pos > coldown as u16 {
                0
            } else {
                coldown as u16 - pos + 1
            };
            pos = 0;
            range += 1;
        }
        if *num_tasks.get(pos as usize).unwrap().1 < range {
            result += coldown as u16 - pos;
            pos = 0;
            range += 1;
        }
        result += 1;
        pos += 1;
    }
    result
}