Phone Bill Calculator

Solution.java

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;

class Solution {


    /**
     * Solutions
     * @param S
     * @return
     */
    public  int solution(String S) {

        int total = 0, max = 0;
        int  sec;
        
        String[] lines = S.split("\n");

        HashMap<String, Integer> phonesTime = new HashMap<>();

        Arrays.stream(lines).map(s -> s.split(",")).forEach(line -> {
            String phone = line[1];
            int  time = timeToSecs(line[0]);


            //Sum up same phone number into one
            if (phonesTime.containsKey(phone)) {
                int oldTime = phonesTime.get(phone);
                phonesTime.put(phone, oldTime + time);
            } else {
                phonesTime.put(phone, time);
            }
        });

        for (String key : phonesTime.keySet()) {
            sec = phonesTime.get(key);
            if (sec >= max) {
                max = sec;
            }
            total += secsToCents(sec);
        }



        //remove promotion rebate
        total -= secsToCents(max);

        return total;
    }

    /**
     * Business logic
     * @param sec
     * @return
     */
    private static int secsToCents(int sec) {

        if (sec < 300) return sec * 3;
        else if (sec % 60 == 0) return (sec / 60) * 150;
        else return ((sec / 60) + 1) * 150;

    }

    /**
     *  timeToSecs
     * @param time
     * @return
     */
    private static int timeToSecs(String  time) {
        DateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
        Date date = null;
        Date reference = null;
        try {
            reference = dateFormat.parse("00:00:00");
            date = dateFormat.parse(time);
        }catch ( Exception ex){

        }
        long seconds = (date.getTime() - reference.getTime()) / 1000L;
        return Math.toIntExact(seconds);

    }

    public static void main(String[] args) {
        String S = "00:01:07,400-234-090\n" +
                "00:05:01,701-080-080\n" +
                "00:05:00,400-234-090";
        Solution s = new Solution();

        int solution = s.solution(S);

        System.out.println(solution);
    }


}