runningReduce
Returns a list containing successive accumulation values generated by applying operation from left to right to each character and current accumulator value that starts with the first character of this char sequence.
inline fun CharSequence.runningReduce(operation: (acc: Char, Char) -> Char): List<Char>(source)
fun main() {
val text = "kotlin"
// runningReduce keeps the running maximum ASCII character
val runningMax = text.runningReduce { acc, c -> if (c > acc) c else acc }
println(runningMax) // prints: [k, o, t, t, t, t]
}