pow.py

"""
[pow(2, n) for n in xrange(10000)]
0.108330011368 sec

[p(2, n) for n in xrange(10000)]
0.289177894592 sec

[bp(2, n) for n in xrange(10000)]
19.3486168385 sec
"""
def p(x, n):
    i, y = n, 1
    while i > 0:
        if i % 2 == 1:
            y = y * x
        x = x * x
        i = i / 2
    return y

def bp(x, n):
    a = 1
    for _ in xrange(n):
        a = a * x
    return a

if __name__ == '__main__':
    import time
    start = time.time()
    [pow(2, n) for n in xrange(10000)]
    print("%s sec" % ( time.time() - start ))

    start = time.time()
    [p(2, n) for n in xrange(10000)]
    print("%s sec" % (time.time() - start))

    start = time.time()
    [bp(2, n) for n in xrange(10000)]
    print("%s sec" % ( time.time() - start ))