#
#   Prints all permutations.
#
def permutation(s, b, e):
    if b+1 == e:
        print(s)
    else:
        for i in range(b, e-1):
            permutation(s, b+1, e)
            c = s[i+1]
            s[i+1] = s[i]
            s[i] = s[b]
            s[b] = c
        permutation(s, b+1, e)
        c = s[b]
        s[b] = s[e-1]
        s[e-1] = c

#
#   Prints all permutations. But in addition doesn't print
#   multiple instances of same value.
#   e.g. abb bab bba  ( doesn't print two abb )
#
def permutation2(s):
    print(s)
    l = len(s)

    while True:
        i = l-1
        while True:
            ii = i
            i = i - 1
            if ord(s[i]) < ord(s[ii]):
                j = l-1
                while ord(s[i]) >= ord(s[j]):
                    j = j - 1
                s[i], s[j] = s[j], s[i]
                s[ii:l] = s[ii:l][::-1]
                print(s)
                break
            if i == 0:
                return

if __name__ == "__main__":
    s = ['a', 'b', 'c', 'd', 'e', 'e']
    permutation(s, 0, len(s))
    print("--------------------------------------------")
    permutation2(s)