Puzzle - Highest product of 3 numbers in an array

Highest Product of triplets in array – Algorithm

Below is a puzzle I got from a colleague when he attended an interview. Trying to solve my way.

Question

• Find the triplet from integer array whose product is highest
• Use single loop.
• Language can be any

Samples

• Input [1,2,3,4] -> [2,3,4]
• Input [-5,-7,4,2,1,9]-> [-5,-7,9]
• Input [-10,-3,-5,0,-20]->[-10,-5,-20]

Approach

Since 2 negative numbers can produce positive product the approach taken was to find the lowest, second lowest, third highest, second highest and first highest numbers and compared their sums as follows.

---

            if (lowest * secondLowest * highest > highest * secondHighest * thirdHighest)
            {
                return new int[3] { lowest, secondLowest, highest };
            }
            else
            {
                return new int[3] { thirdHighest, secondHighest, highest };
            }

---

Finding the numbers is the trick. One implementation can be found in below location.
https://github.com/joymon/puzzles/tree/master/Numbers/HighestProductOfTripletInArray

Comment if there are any other simple implementations.

Happy coding...