# permutations of a string done recursively
# ECS 10, May 26, 2009
# Matt Bishop

# function to compute permutations of a string
# parameter: s, a string
# returns: list of all permutations of the string
def perm(s):
    # base case: empty string
    if s == "":
        return [ s ]
    # recursive case
    # start empty
    listperm = []
    # for each string in permutations of remaining str
    for w in perm(s[1:]):
        # put the first char in each of the possible places in the string
        for p in range(len(w)+1):
            # append new string to list
            listperm.append(w[:p] + s[0] + w[p:])
    # return list
    return listperm