Shortest Longest Common Subsequence Code
Python - 665 644

Indentation levels:

1: space
2: tab
3: tab + space
4: 2 tabs
5: 2 tabs + space


The code defines a function o, which takes a list of strings as arguments and returns one of the LCS's for the strings.

def o(t):
 t=[[y for y in x if y in reduce(lambda x,y:x.intersection(y),t,set(t[0]))]for x in t];l=map(len,t);C=[0]*reduce(lambda x,y:x*-~y,l,1);y=lambda z:[x-1for x in z];m=len(t);e=enumerate
 def g(h):
    r,x=0,1
    for k,j in e(h):r+=-~j*x;x*=-~l[k]
    return r
 def f(h):
    i=len(h)
    if i==m:
     b=g(h);c=t[0][h[0]]
     for k,j in e(h):
         if t[k][j]!=c:break
     else:C[b]=1+C[g(y(h))];return
     r=0
     for k,_ in e(h):a=h[:];a[k]-=1;r=max(r,C[g(a)])
     C[b]=r;return
    for j,_ in e(t[i]):f(h+[j])
 def p(h):
    if min(h)==-1:return''
    v=C[g(h)]
    for k,_ in e(h):
        a=h[:];a[k]-=1
        if v==C[g(a)]:return p(a)
    return p(y(h))+t[0][h[0]]
 f([]);return p(y(l))


Test code:

tests = [
"""
a
ab
""",
"""
aaaaxbbbb
bbbbxcccc
ccccxaaaa
""",
"""
hxbecqibzpyqhosszypghkdddykjfjcajnwfmtfhqcpavqrtoipocijrmqpgzoufkjkyurczxuhkcpehbhpsuieqgjcepuhbpronmlrcgvipvibhuyqndbjbrrzpqbdegmqgjliclcgahxoouqxqpujsyfwbdthteidvigudsuoznykkzskspjufgkhaxorbrdvgodlb
qnnprxqpnafnhekcxljyysobbpyhynvolgtrntqtjpxpchqwgtkpxxvmwwcohxplsailheuzhkbtayvmxnttycdkbdvryjkfhshulptkuarqwuidrnjsydftsyhuueebnrjvkfvhqmyrclehcwethsqzcyfvyohzskvgttggndmdvdgollryqoswviqurrqhiqrqtyrl
""",
"""
riikscwpvsbxrvkpymvbbpmwclizxlhihiubycxmxwviuajdzoonjpkgiuiulbjdpkztsqznhbjhymwzkutmkkkhirryabricvhb
jnrzutfnbqhbaueicsvltalvqoorafnadevojjcsnlftoskhntashydksoheydbeuwlswdzivxnvcrxbgxmquvdnfairsppodznm
kzimnldhqklxyezcuyjaiasaeslicegmnwfavllanoolkhvqkjdvxrsjapqqwnrplcwqginwinktxnkfcuuvoyntrqwwucarfvjg
""",
"""
rblartqkfggrjpiipuzzypkycnyckkcqceeujiyy
yfpnedyjtiwrhyuktripdwyvgkblzodeufkelhub
ywcyboxwqkibwvredkrbdsyudkulpvmhixeqxynh
bnxwahbzhwjxkotnvbxrojkkldtsodtjmvdrmbgr
""",
"""
bwfscmotshoczmduwaev
coywaaizdaxjovipsmeh
dobzcpoiedenzlfdjpiu
bbhfeqscvvbwkuoxdoge
drqrzwbcpcsvneodelja
""",
"""
nqrualgoedlf
jgqorzglfnpa
fgttvnogldfx
pgostsulyfug
sgnhoyjlnfvr
wdttgkolfkbt
""",
"""
epopyfuhgowedpiqpgfj
ddxyestqynpwmytxhozm
ptubgzyqqksieoovuezv
tovotqmnhgzttfpywjgr
aomvytkgaijlgqzkljls
vzvxpaixrnprxvenbbuo
syfuwxlpcyontqlmfvib
arxleuomstkjegpduwcx
xgqrxaopouvkvwgbzewn
yggunddigctgpnuztzai
izroomywwztdymqszsuo
kiawjnxjncdtufhkrjsp
"""
]

for s in tests:
 print o(s.strip().split())


Time it takes to run the tests on my computer:

$ time python 52808-shortest-longest-common-subsequence-code-golfed.py
a
x
hecbpyhogntqtpcqgkxchpsieuhbncvhuqndbjqmclchqyfhtdvgoysuhrrl
icsvllvanlktywuar
krkk
code
golf

        9.03 real         8.99 user         0.03 sys