>>147
Rubyで。
N=11が限界みたいだ。

N = 11
org_ary = (1..N).to_a
wrk_ary = org_ary.dup

cnt = 0
while (wrk_ary = wrk_ary.shuffle) != org_ary
cnt += 1
end
p cnt

# 実行結果
# ruby odai-10-147.rb 17.10s user 0.15s system 96% cpu 17.906 total
# 22093802
# ruby odai-10-147.rb 35.19s user 0.27s system 98% cpu 35.950 total
# 6677838
# ruby odai-10-147.rb 10.64s user 0.11s system 96% cpu 11.170 total
# 26014838