作者: 
retard (Baby baby~~)   
2014-05-12 04:57:28這應該是個 map reduce 的題目吧
l = [2, 3, 4, 5, 0, 1, 2, 3, 4, 2, 3, 5]
def func_map(a):
    return [set([a]), set([a])]
def func_reduce(am, bm):
    uaset, aset = am
    ubset, bset = bm
    unset = (uaset - bset) | (ubset - aset)
    nset = aset | bset
    return [unset, nset]
reduce(func_reduce, map(func_map, l))
先把值 map 成 uniq set, all number set
再 reduce 成 uniq set, all number set