List<int> absolutePermutation(int n, int k)
{
    if (k == 0) return Enumerable.Range(1, n).ToList();
    
    HashSet<int> result = new();

    for (int i = 1; i <= n; i++)
    {
        var permutationElement = i > k ? i - k : i + k;
        if (permutationElement > n || result.Contains(permutationElement))
        {
            permutationElement = i < k ? i - k : i + k;
            if (permutationElement > n || result.Contains(permutationElement))
            {
                return new List<int> { -1 };
            }
        }
        result.Add(permutationElement);
    }
    return result.ToList();
}

vector<int> absolutePermutation(int n, int k) {
vector<int>arr,brr;
for(int i=1;i<=n;i++) arr.push_back(i);
if(k==0) return arr;
if(n%(2*k)==0){
    for(int i=0;i<n/(2*k);i++){
        for(int j=1;j<=k;j++) brr.push_back((2*k*i)+k+j);
        for(int j=1;j<=k;j++){
            brr.push_back(2*k*i+j);
        }       
    }
}
if(brr.size()==0) return {-1};
    return brr;
}

# P 1 based indexing
    # hashMap for 1 to N values (P)
    # |pos[i]-i|=k
    # pos[i]-i=-k    pos[i]-i=k
    # pos[i]=-k+i    pos[i]=k+i
    #   -1  3
    #   0   4
    #   1   5
    #   2   6
    # k=4
    iValues={}
    posValues={}
    for i in range(1,n+1):
        iValues[i]=(-k+i,k+i)
        posValues[i]=False
    result = []
    #iValues
    for i in range(1,n+1):
        if(iValues[i][0]>0 and posValues[iValues[i][0]]==False):
            posValues[iValues[i][0]]=True
            result.append(iValues[i][0])
        elif(iValues[i][1]<=n and posValues[iValues[i][1]]==False):
            posValues[iValues[i][1]]=True
            result.append(iValues[i][1])
        else:
            return [-1]
            
    return result
                
    #spaceComplexity 0(n)
    #runtimeComplexity 0(n)

public static List<Integer> absolutePermutation(int n, int k) {
        Integer[] result = new Integer[n];
        int idx;
        for (int value = 1; value <= n; value++) {
            idx = value - k;
            if (idx <= n && idx > 0 && result[idx - 1] == null) {
                result[idx - 1] = value;
            } else {
                idx = value + k;
                if (idx <= n && idx > 0 && result[idx - 1] == null) {
                    result[idx - 1] = value;
                } else {
                    result = new Integer[1];
                    result[0] = -1;
                    return Arrays.asList(result);
                }
            }
        }
        return Arrays.asList(result);
    }