day1/exercise/find_pow_2.py
author Puneeth Chaganti <punchagan@fossee.in>
Fri, 06 Nov 2009 17:56:22 +0530
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def is_pow_2(n):
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    bin_count = 0
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    while n > 0:
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        if n % 2 == 1:
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            bin_count += 1
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        if bin_count > 1:
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            return False
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        n /= 2
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    return bin_count == 1
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def collatz_pow_2(n):
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    if n == 1: return 4
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    if n == 2: return 4
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    collatz_pow_2 = []
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    while n > 2:
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        print n, 
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        if is_pow_2(n):
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            collatz_pow_2.append(n)
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        if n % 2:
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            n = n * 3 - 1
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        else:
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            n /= 2 
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    return max(collatz_pow_2)
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import sys
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collatz_pow_2(int(sys.argv[1]))