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51
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1 # You are required to implement a production-level code live, using concurrency. Complete within 60 minutes. Suppose you are developing a simple concurrent counter that can correctly update the count in a multi-threaded environment. The initial count value is 0. Ensure it executes in 100 threads, where each thread increments the counter by 1 every second for 10 seconds. Calculate the final count after parallel execution.
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2 #
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3 # Input: None
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4 #
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5 # Output: An integer representing the final count.
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6 #
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7 # Constraints:
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8 #
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9 # The code must use multi-threading or multi-processing techniques.
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10 # Ensure thread safety.
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11
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12
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13 # - 100 threads
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14 # - each tread update counter by 1 everyseconds by 10 seconds
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15 from threading import Lock
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16 from time import sleep
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17 from concurrent.futures import ThreadPoolExecutor
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18
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19
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20 SLEEP_IN_SECONDS = 1
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21 EXECUTION_TIME_IN_SECONDS = 3
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22 NUMS_THREADS = 100
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23
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24 class Counter:
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25
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26 def __init__(self):
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27 self._value = 0
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28 self.lock = Lock()
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29
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30 def get(self):
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31 return self._value
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32
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33 def increment(self):
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34 with self.lock:
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35 value = self.get()
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36 sleep(0.01)
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37 self._value = value + 1
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38
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39 def worker(counter: Counter):
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40 for _ in range(EXECUTION_TIME_IN_SECONDS):
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41 counter.increment()
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42 sleep(SLEEP_IN_SECONDS)
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43
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44 def main():
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45 counter = Counter()
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46 with ThreadPoolExecutor(max_workers=NUMS_THREADS) as executor:
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47 for _ in range(NUMS_THREADS):
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48 executor.submit(worker, counter)
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49 print(counter.get())
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50
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51 main()
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