Task Scheduler

def leastInterval(tasks, n):
    count = collections.Counter(tasks)
    maxHeap = [-cnt for cnt in count.values()]
    heapq.heapify(maxHeap)
    
    time = 0
    q = collections.deque() # [-cnt, idleTime]
    
    while maxHeap or q:
        time += 1
        
        if maxHeap:
            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