Create 621-Task-Scheduler.py

Author: neetcode-gh

621-Task-Scheduler.py

@@ -0,0 +1,20 @@
+class Solution:
+    def leastInterval(self, tasks: List[str], n: int) -> int:        
+        count = Counter(tasks)
+        maxHeap = [-cnt for cnt in count.values()]
+        heapq.heapify(maxHeap)
+        
+        time = 0
+        q = deque() # pairs of [-cnt, idleTime]
+        while maxHeap or q:
+            time += 1
+            
+            if not maxHeap:
+                time = q[0][1]
+            else:
+                cnt = 1 + heapq.heappop(maxHeap)
+                if cnt:
+                    q.append([cnt, time + n])
+            if q and q[0][1] == time:
+                heapq.heappush(maxHeap,  q.popleft()[0])
+        return time