Fast functions for intersecting sorted lists in Kotlin, returning Lists or Sequences

ListIntersection.kt

import kotlin.math.*

object ListIntersection {

    fun <T : Comparable<T>> safeIntersection(l1: List<T>, l2: List<T>) : List<T> {
        return l1.intersect(l2).sorted()
    }

    // https://stackoverflow.com/a/33963306/480176

    fun <T : Comparable<T>> fastIntersection(a1: List<T>, a2: List<T>) : List<T> {
        return fastIntersectionSequence(a1, a2).toList()
    }

    fun <T : Comparable<T>> fastIntersectionSequence(a1: List<T>, a2: List<T>) : Sequence<T> {
        val s1 = a1.size
        val s2 = a2.size
        return if (s1 > 0 && s1 + s2 > min(s1, s2) * ln(max(s1, s2).toDouble()) * 1.4426950408889634)
            bSearchIntersectionSequence(a1, a2)
        else
            linearIntersectionSequence(a1, a2)
    }

    fun <T : Comparable<T>> linearIntersectionSequence(a1: List<T>, a2: List<T>) : Sequence<T> {
        return sequence {
            val s1 = a1.size
            val s2 = a2.size
            var i1 = 0
            var i2 = 0
            while (i1 < s1 && i2 < s2) {
                val v1 = a1[i1]
                val v2 = a2[i2]
                if (v1 == v2) {
                    yield(v1)
                    i1 += 1
                    i2 += 1
                }
                else if (v1 < v2) i1 += 1
                else i2 += 1
            }
        }
    }

    fun <T : Comparable<T>> bSearchIntersectionSequence(a1: List<T>, a2: List<T>) : Sequence<T> {
        return sequence {
            val s1 = a1.size
            val s2 = a2.size
            var i1 = 0
            var i2 = 0
            var temp : Int
            while (i1 < s1 && i2 < s2) {
                val v1 = a1[i1]
                val v2 = a2[i2]
                if (v1 == v2) {
                    yield(v1)
                    i1 += 1
                    i2 += 1
                }
                else if (v1 < v2) {
                    temp = a1.binarySearch(v2, i1)
                    i1 = if (temp < 0) -(temp + 1) else temp
                }
                else {
                    temp = a2.binarySearch(v1, i2)
                    i2 = if (temp < 0) -(temp + 1) else temp
                }
            }
        }
    }
}