find_original_array_from_doubled_array.go

package main

import"sort"

funcfindOriginalArray(changed []int) []int {
//if the total len is odd, return empty array
iflen(changed)%2!=0 {
return []int{}
 }
//sort the array
sort.Ints(changed)

//populate the frequency map
freq:=make(map[int]int)
for_, val:=rangechanged {
freq[val]++
 }

result:= []int{}
//iterate thru the original array
for_, val:=rangechanged {
cnt:=freq[val]
//no need for check for existence ; element would be present
ifcnt>0 {
//if the count is greater than 0
//reduce the count
freq[val]--
//check for double
dbl:=val*2
//if present and value is greater than 0
//then it is candidate
//however if not present or count is not greater
//than zero then return empty array
ifv, ok:=freq[dbl]; ok {
ifv>0 {
result=append(result, val)
freq[dbl]--
 } else {
return []int{}
 }
 } else {
return []int{}
 }
 }
 }

returnresult
}