compareMapInits.kt

fun compareMapInits(repeat: Int, size: Int) {
    println(">>> compareMapInits for $size elements (repeated $repeat times)")
    var totalMutableMapRuntime: Long = 0
    var totalHashMapRuntime : Long = 0
    var countHashMapSlower = 0
    repeat(repeat) {
        // mutableMapOf()
        val startTime = System.currentTimeMillis()
        val map = mutableMapOf<Int, Int>()
        (0..size).forEach {
            map[it] = it
        }
        val mutableMapRuntime = System.currentTimeMillis() - startTime
        totalMutableMapRuntime += mutableMapRuntime
        // HashMap()
        val startTime2 = System.currentTimeMillis()
        val map2 = HashMap<Int, Int>()
        (0..size).forEach {
            map2[it] = it
        }
        val hashMapRuntime = System.currentTimeMillis() - startTime2
        totalHashMapRuntime += hashMapRuntime

        if (hashMapRuntime > mutableMapRuntime) {
            countHashMapSlower++
        }
    }
    println("mutableMapOf() total time taken: $totalMutableMapRuntime ms")
    println("HashMap() total time taken: $totalHashMapRuntime ms")
    println("How often is HashMap() slower? ${countHashMapSlower}/$repeat")
    println("<<<")
}