Project Euler – Problem # 36 – Solved with Python

Problem:

The decimal number, 585 = 10010010012 (binary), is palindromic in both bases.

Find the sum of all numbers, less than one million, which are palindromic in base 10 and base 2.

(Please note that the palindromic number, in either base, may not include leading zeros.)

One Possible Solution:

# Python version = 2.7.1
# Platform = win32

def binary_rep(i):
    """Take decimal i and convert to binary with
    built in function bin, slice off first two
    characters."""
    x = bin(i)
    y = x[2:]
    return y

def reverse_binary(y):
    """Take binary number y and reverse characters"""
    x = y[::-1]
    return x

def reverse_decimal(i):
    """Take decimal number i and reverse characters"""
    y = str(i)
    d = y[::-1]
    return d

def main():
    """Main Program"""
    L = []
    Answer = 0
    for i in range(1, 1000000):
        x = binary_rep(i)
        y = reverse_binary(x)
        if x == y:
            a = int(reverse_decimal(i))
            if i == a:
                L.append(i)
        else:
            continue
    Answer = sum(L)
    print "Sum = ", Answer
        
if __name__ == '__main__':
    main()
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1 Comment

  1. well…

    sum = 0
    for i in range(1000000):
    if str(i) == str(i)[::-1] and “{0:0b}”.format(i) == “{0:0b}”.format(i)[::-1]:
    sum+=i
    print sum

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