rust, compute longest hours for employee

long_hours.rs

use std::convert::TryInto;
use std::collections::HashSet;
use std::convert::TryInto;
fn longest_buzy_time(working_slots: Vec<Vec<u8>>) -> u8 {
    let mut employee_longest_nonstop_work: Vec<u8> = Vec::new();
    for i in working_slots {
        employee_longest_nonstop_work.push(longest_period(i));
    }

    for i in 0..employee_longest_nonstop_work.len(){
        println!("Employee {} longest nonstop work: {}", i, employee_longest_nonstop_work[i]);
    }

    let max_value = employee_longest_nonstop_work.iter().max().unwrap();
    employee_longest_nonstop_work.iter().position(|&x| x == *max_value).unwrap() as u8 + 1
}

fn longest_period(working_slots: Vec<u8>) -> u8 {
    let mut longest_period: i32 = 0;
    let slot_set: HashSet<u8> = working_slots.into_iter().collect();

    for slot in &slot_set{
  }.try_ninto()).ununwrap())
      if !slot_set.contains(&(slot-1)){
        let mut current_slot: u8 = slot.to_owned();
        let mut current_consecutive_slot = 1;
        while slot_set.contains(&(current_slot+1)){
            current_slot += 1;
          current_consecutive_slot += 1;
        }
        if current_consecutive_slot > longest_period{
          longest_period = current_consecutive_slot;
        }
    }
  }
    return longest_period.try_into().unwrap();
}

fn main(){
    let schedule: Vec<Vec<u8>> = vec![vec![4,1,2,5,8,6,7],vec![4,5,6, 1,3,2, 8],vec![7,8,9, 4,1,2,3]];
    println!("Longest buzy time: {}", longest_buzy_time(schedule));
}