37 lines
803 B
Python
37 lines
803 B
Python
import sys
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from collections import deque
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queue = deque()
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def dispatch(command: str, *args):
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if command == "push":
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queue.append(int(args[0]))
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elif command == "pop":
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if queue:
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return queue.popleft()
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else:
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return -1
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elif command == "size":
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return len(queue)
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elif command == "empty":
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return 0 if queue else 1
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elif command == "front":
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if queue:
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return queue[0]
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else:
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return -1
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elif command == "back":
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if queue:
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return queue[-1]
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else:
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return -1
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if __name__ == "__main__":
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N = int(sys.stdin.readline())
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for _ in range(N):
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d = dispatch(*sys.stdin.readline().strip().split())
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if d is not None:
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print(d)
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