func duplicateInArray(nums []int) int {

for _,value:=range nums{
    if value<0 || value>=len(nums){
        return -1
    }
}

ss:=make([]int,0)

for i,_:=range nums{
    flag:=true
    for j,_ :=range ss{
        if nums[i]==ss[j]{
            flag = false
            return nums[i]
        }
    }
    if flag {
        ss=append(ss,nums[i])
    }
}

return -1

}