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52 lines
1.1 KiB
Python
52 lines
1.1 KiB
Python
"""Segmented Sieve."""
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import math
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def sieve(n):
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"""Segmented Sieve."""
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in_prime = []
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start = 2
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end = int(math.sqrt(n)) # Size of every segment
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temp = [True] * (end + 1)
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prime = []
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while start <= end:
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if temp[start] is True:
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in_prime.append(start)
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for i in range(start * start, end + 1, start):
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if temp[i] is True:
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temp[i] = False
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start += 1
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prime += in_prime
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low = end + 1
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high = low + end - 1
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if high > n:
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high = n
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while low <= n:
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temp = [True] * (high - low + 1)
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for each in in_prime:
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t = math.floor(low / each) * each
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if t < low:
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t += each
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for j in range(t, high + 1, each):
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temp[j - low] = False
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for j in range(len(temp)):
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if temp[j] is True:
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prime.append(j + low)
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low = high + 1
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high = low + end - 1
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if high > n:
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high = n
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return prime
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print(sieve(10**6))
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