[[問題文>練習問題#u170a96a]]
 arr = [12, 6, 8, 3, 10, 1, 0, 9]
 a = zip(range(len(arr)), arr)
 a.sort(cmp=lambda x,y: cmp(x[1], y[1]), reverse=True)
 print '\n'.join('%d -> %d' % (x, y) for x, y in a[:3])
 a = zip(xrange(len(arr)), arr)
 a.sort(key=lambda e: e[1], reverse=1)
 print '\n'.join('{0} -> {1}'.format(x, y) for x, y in a[:3])

#初心者用
 a = [12, 6, 8, 3, 10, 1, 0, 9]
 for i in range(3):
	 b = max(a)
	 z = min(a)
	 c = a.index(b)
	 print str(c) + " -> " + str(b)
	 a[c] = z - 1