chuanconggao

from collections import defaultdict

def frequent_rec(patt, mdb):
    results.append((len(mdb), patt))

    occurs = defaultdict(list)
    for (i, startpos) in mdb:
        seq = db[i]
        for j in range(startpos + 1, len(seq)):
            l = occurs[seq[j]]

chuanconggao

def anagrams(s):
    return [s] if len(s) == 0 else [
        w[:pos] + s[:1] + w[pos:]
        for w in anagrams(s[1:])
        for pos in range(len(w) + 1)
    ]

anagrams("abc")
# returns ['abc', 'bac', 'bca', 'acb', 'cab', 'cba']