fun stringElements4(s: String, list: List<Int>): String = buildString { list.map { it * 2 } .filter { it % 2 == 0 } .forEach { append(s[it]) } } fun main() { println(stringElements4("abcdefgh", listOf(3, 2, 1, 0))) println(stringElements4("hello there", listOf(0, 1, 2, 4))) println(stringElements4("This is a test", listOf(4, 2, 2, 0))) println(stringElements4("How was your day?", listOf(0, 4, 4, 3, 7, 7))) println(stringElements4("Welcome to ReadingBat", listOf(1, 4, 2, 6, 8))) }