Create 621-Task-Scheduler.java

Author: SharmaTushar1

java/621-Task-Scheduler.java

@@ -0,0 +1,28 @@
+class Solution {
+    public int leastInterval(char[] tasks, int n) {
+        if (n==0) return tasks.length;
+        PriorityQueue<Integer> pq = new PriorityQueue<>((a,b)->b-a);
+        Queue<Pair<Integer, Integer>> q = new LinkedList<>();
+        int[] arr = new int[26];
+        for (char c: tasks) 
+            arr[c-'A']++;
+        for (int val: arr) 
+            if (val>0) 
+                pq.add(val);
+        int time = 0;
+        // System.out.println(pq);
+        // System.out.println(q);
+        while ((!pq.isEmpty() || !q.isEmpty())) {
+            if (pq.isEmpty()) {
+                time = Math.max(q.peek().getValue(), time);
+                pq.add(q.poll().getKey());
+            }
+            int val = pq.poll();
+            val--;
+            time++;
+            if (val>0) q.add(new Pair(val, time+n));
+//             System.out.println(q + " "+ time);
+        }
+        return time;
+    }
+}