class Solution {
private val delimiters = arrayOf<String>(
" ",
"\"",
"!",
"?",
"\'",
",",
";",
"."
)
fun mostCommonWord(paragraph: String, banned: Array<String>): String
= paragraph
.split(*delimiters)
.map{ it.lowercase() }
.filter{ it.isNotBlank() && !banned.contains(it.toString()) }
.groupingBy{ it }
.eachCount()
.maxBy{ it.value }
.key
}