お題：文字列を先頭から見て同じところまで除去 solved by Groovy

dropStartsSameTest.groovy

// http://d.hatena.ne.jp/fumokmm/20110812/1313138407
def dropStartsSame(String... args) {
  if (args.any{!it}) return args
  args*.substring(
    args*.toList().transpose().with{
      def i=0; it.collect{[i++, it]}
    }.with{ dup ->
      dup.find{ it[1].unique().size() != 1 }.with {
        it ? it[0] : dup.last()[0]+1
      }
    }
  )
}

assert ['def', '123'] == dropStartsSame('abcdef', 'abc123')
assert ['うえお', 'さんさん', 'どる'] == dropStartsSame('あいうえお', 'あいさんさん', 'あいどる')
assert ['12345', '67890', '12abc'] == dropStartsSame('12345', '67890', '12abc')
assert ['', 'b', 'bc'] == dropStartsSame('a', 'ab', 'abc')
assert [null, 'a', 'ab'] == dropStartsSame(null, 'a', 'ab')
assert ['', 'a', 'ab'] == dropStartsSame('', 'a', 'ab')