90%, 12Line
Code\n\nfrom sortedcontainers import SortedList\nclass Solution:\n    def busiestServers(self, k: int, arrival: List[int], load: List[int]) -> List[int]:\n     
# Code\n```\nfrom sortedcontainers import SortedList\nclass Solution:\n    def busiestServers(self, k: int, arrival: List[int], load: List[int]) -> List[int]:\n        running = SortedList()\n        avail = SortedList(range(k))\n        d = defaultdict(int)\n        for i in range(len(arrival)):\n            while running and running[0][0] <= arrival[i]:\n                avail.add(running.pop(0)[1])\n            if avail:\n                t = avail.pop((avail.bisect_left(i%k)%len(avail)))\n                d[t] += 1\n                running.add((load[i]+arrival[i], t))\n        t = max(d.values())\n        return [key for key in d if d[key] == t]\n\n\n""" heap version\nclass Solution:\n    def busiestServers(self, k: int, arrival: List[int], load: List[int]) -> List[int]:\n        running = []\n        avail = list(range(k))\n        d = [0] * k\n        for i in range(len(arrival)):\n            while running and running[0][0] <= arrival[i]:\n                heappush(avail, (heappop(running)[1]-i)%k+i)\n            if avail:\n                t = heappop(avail)%k\n                d[t] += 1\n                heappush(running, (load[i]+arrival[i], t))\n        mx = max(d)\n        return [i for i in range(len(d)) if d[i] == mx]\n"""\n```
['Python3']