Python code:

import timeit

def clever():
    for n in xrange(1, 500):
        for m in xrange(n + 1, 500):
            a = m*m - n*n
            b = 2 * m * n
            c = m*m + n*n
            if a + b + c == 1000 and (a*a + b*b == c*c):
                print "Clever: a = %d, b = %d, c = %d" % (a, b, c)
                break
    return True

def naive():
     for a in xrange(1,999):
        for b in xrange(a+1, 999-a):
            c = 1000 - (b + a)
            if a*a+b*b == c*c:
                print "Naive: a = %d, b = %d, c = %d" % (a, b, c)
                break
     return True

if __name__ == '__main__':
    print("Clever executed in %f seconds" %
           timeit.timeit(clever, number=1))
    print("Naive executed in %f seconds" %
           timeit.timeit(naive, number=1))