func countTriplets(arr []int64, r int64) int64 {
    pair := map[int64]int{}
    triple := map[int64]int{}
    count := 0
    for _, v := range arr{
        if c, ok := triple[v]; ok{
            count += c
        }
        if c, ok := pair[v]; ok{
            triple[v*r] += c
        }
        pair[v*r]++
    }
    return int64(count)
}