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  1. Prepare
  2. Algorithms
  3. Implementation
  4. Beautiful Triplets
  5. Discussions

Beautiful Triplets

  • dahuaxie
     + 0 comments

    i learned this elegant solution from a similar problem "count triplets", where it is a geometric series ak = aj *d, aj = ai *d:

    func beautifulTriplets(d int32, arr []int32) int32 {

    // Write your code here
pair, triple := map[int32]int32{}, map[int32]int32{}
var res int32
for _, a := range arr {
    if c, ok := triple[a]; ok {
        res += c
    }
    if c, ok := pair[a]; ok {
        triple[a+d] += c
    }
    pair[a+d]++
}
return res

    }