package main
import "fmt"
func findElementThatAppearsOnceInArray(arr []int) int {
mp := make(map[int]int)
for _, x := range arr {
mp[x]++
}
for k, v := range mp {
if v == 1 {
return k
}
}
return -1
}
func main() {
arr:= []int{3, 5, 5, 2, 7, 3, 2, 8, 8, 3, 2, 5, 8}
fmt.Println(findElementThatAppearsOnceInArray(arr))
}
/*
run:
7
*/