fun removeMiddleChars(str: String, n: Int): String {
val length = str.length
val start = (length - n) / 2
return str.removeRange(start, start + n)
}
fun main() {
val str = "abc123def"
val n = 3
val result = removeMiddleChars(str, n)
println(result)
}
/*
run:
abcdef
*/