X power n

fun myPow(x: Double, n: Int): Double {
    if (n == 0 || x == 1.0) return 1.0
    if (n == 1) return x
    val power: Long = if (n > 0) n.toLong() else -n.toLong()
    var res = 1.0
    for (i in 1..power) {
        res*=x
    }
    return if (n > 0) res else 1/res
}