tasks has cooldown time, give an input task id array, output finish time

input: AABCA

A--ABCA

output:7

 package fb;

 import java.util.*;

 public class Scheduler {

     public int task(int[] tasks, int cooldown) {

         int time = 0;

         HashMap<Integer, Integer> map = new HashMap<Integer, Integer>();

         StringBuilder output = new StringBuilder();

         for (int i=0; i<tasks.length; i++) {

             if (!map.containsKey(tasks[i]) || time>=map.get(tasks[i])) {

                 map.put(tasks[i], time+cooldown);

                 time++;

                 output.append(tasks[i]);

             }

             else { // time < map.get(tasks[i])

                 for (int k=time; k<map.get(tasks[i]); k++) {

                     output.append("-");

                 }

                 time = map.get(tasks[i]);

                 map.put(tasks[i], time+cooldown);

                 time++;

                 output.append(tasks[i]);

             }

         }

         return time;

     }

     public static void main(String[] args) {

         Scheduler sc = new Scheduler();

         //int res = sc.task(new int[]{1,1,2,3,1}, 3);

         int res = sc.task(new int[]{1,2,1,2,3}, 3);

         //String output = sc.task(new int[]{1,2,2,1,3}, 3);

         System.out.println(res);

         //System.out.println(output);

     }

 }