Simple programming exercise with unionSets

puddles.go

package main

import "fmt"

type Set struct {
  pos int
  value int
}

func makeSet(position int, value int) Set {
  return Set{position, value}
}

func findSet(setA Set, unionList [][]Set) (*[]Set, [][]Set) {
  for i := 0; i < len(unionList); i++ {
    for _, set := range(unionList[i]) {
      if set.pos == setA.pos {
        return &unionList[i], unionList
      }
    }
  }
  newUnion := []Set{setA}
  newList := append(unionList, newUnion)
  return &newUnion, newList
}

func unionSet(union *[]Set, set Set) {
  *union = append(*union, set)
}

func validUnion(union []Set, startPos int, endPos int) bool {
  return (union[0].pos != startPos) && (union[len(union)-1].pos != endPos)
}

func validMerge(unionA []Set, setB Set) bool {
  lastSet  := unionA[len(unionA)-1]
  return (lastSet.pos < setB.pos) && (lastSet.pos + 1 == setB.pos)
}

func getExtremes(area []int) (int, int) {
  min := 100000
  max := 0

  for _, value := range area {
    if min > value {
      min = value
    }
    if max < value {
      max = value
    }
  }
  return min, max
}

func waterRetention(area []int) int {
  var setList []Set
  var unionA *[]Set
  var unionList [][]Set
  total := 0
  min, max := getExtremes(area)

  for max >= min {

    setList = make([]Set, 0)
    unionList = make([][]Set, 0)

    for index, value := range area {
      if value <= min {
        setList = append(setList, makeSet(index, value))
      }
    }

    for _, setA := range setList {
      for _, setB := range setList {
        unionA, unionList = findSet(setA, unionList)
        if validMerge(*unionA, setB) {
          unionSet(unionA, setB)
        }
      }
    }

    for _, union := range unionList {
      if validUnion(union, 0, ) {
        total += len(union)
      }
    }
    min += 1
  }
  fmt.Printf("[W] Total Retained Water Value: %d!\n", total)
  return total
}

func main () {
  waterRetention([]int{ 2, 5, 1, 2, 3, 4, 7, 7, 6 })
  waterRetention([]int{ 2, 5, 1, 2, 3, 4, 7, 7, 6, 5, 4, 4, 4, 2, 3 })
  waterRetention([]int{ 2, 5, 1, 3, 1, 2, 1, 7, 7, 6 })
  waterRetention([]int{ 2, 7, 2, 7, 4, 7, 1, 7, 3, 7 })
  waterRetention([]int{ 7, 7, 7, 2, 7, 7, 7, 7, 7, 7, 7 })
  waterRetention([]int{ 6, 7, 7, 4, 3, 2, 1, 5, 2 })
  waterRetention([]int{ 2, 5, 1, 2, 3, 4, 7, 6, 2, 7, 1, 2, 3, 4, 5, 4 })
}