22 lines
522 B
Python
22 lines
522 B
Python
import sys
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input = sys.stdin.readline
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nums = [int(input()) for _ in range(int(input()))]
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num_max = max(nums)
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isPrime = [True for _ in range(num_max+1)]
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isPrime[0], isPrime[1] = False, False
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for i in range(2,int(num_max**0.5)+1) :
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if isPrime[i] :
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for j in range(i*i, num_max+1, i) :
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isPrime[j] = False
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result = []
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for n in nums :
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count = 0
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for i in range(2,n//2 + 1) :
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if isPrime[n-i] and isPrime[i] :
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count += 1
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result.append(str(count))
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print('\n'.join(result)) |