lol i dont understand 100% but almost 80%, but whatever

App.java

public class App {
    private static int fieldWidth, fieldSize;
    private static long[] result;
    private static int[] fieldCheck, fieldCheckR;
    private static int[] rotationOffset = new int[8],
            rotationX = new int[8],
            rotationY = new int[8];
    private static int linkData[] = new int[4];
    public static void main(String[] args) {
        int cell = 8;
        if (cell < 1) {
            return;
        } if (cell == 1) {
            count(2);
        } else {
            count(cell);
        }
        for (int i = 0; i != cell + 1; i++) {
            System.out.println(result[i]);
        }
    }
    private static void count(int cell) {
        fieldWidth = cell * 2 - 2;
        fieldSize = (cell - 1) * (cell -1) * 2 + 1;
        result = new long[cell + 1];

        int[] pnField = new int[fieldSize];
        int[] pnPutList = new int[fieldSize];
        fieldCheck = new int[cell * cell];
        fieldCheckR = new int[cell * cell];
        linkData[0] = 1;
        linkData[1] = fieldWidth;
        linkData[2] = -1;
        linkData[3] = - fieldWidth;
        initOffset(cell);
        countSub(cell, 0, pnField, pnPutList, 0 , 1);
    }
    private static void countSub(int n, int lv, int[] field, int[] putList,
                     int putno, int putlast) {
        check(field, n, lv);
        if (n == lv) {
            return;
        }

        for (int i = putno; i != putlast; i++) {
            int pos = putList[i];
            field[pos] |= 1;
            int k = 0;
            for (int j = 0; j != 4; j++) {
                int pos2 = pos + linkData[j];
                if (0 <= pos2 && pos2 < fieldSize && field[pos2] == 0) {
                    field[pos2] = 2;
                    putList[putlast + k] = pos2;
                    k++;
                }
            }
            countSub(n, lv + 1, field, putList, i + 1, putlast + k);
            for (int j = 0; j != k; j++) {
                field[putList[putlast + j]] = 0;
            }
            field[pos] = 2;
        }
        for (int i = putno; i != putlast; i++) {
            int pos = putList[i];
            field[pos] &= -2;
        }
    }

    private static void initOffset(int n) {
        rotationOffset[0] = 0;
        rotationX[0] = 1;
        rotationY[0] = n;
        // 90
        rotationOffset[1] = n - 1;
        rotationX[1] = n;
        rotationY[1] = -1;
        // 180
        rotationOffset[2] = n * n - 1;
        rotationX[2] = -1;
        rotationY[2] = -n;
        // 270
        rotationOffset[3] = n * n - n;
        rotationX[3] = -n;
        rotationY[3] = 1;

        rotationOffset[4] = n - 1;
        rotationX[4] = -1;
        rotationY[4] = n;
        // 90
        rotationOffset[5] = 0;
        rotationX[5] = n;
        rotationY[5] = 1;
        // 180
        rotationOffset[6] = n * n - n;
        rotationX[6] = 1;
        rotationY[6] = -n;
        // 270
        rotationOffset[7] = n * n - 1;
        rotationX[7] = -n;
        rotationY[7] = -1;
    }

    private static void check(int[] field, int n, int lv) {
        for (int i = 0; i != n * n; i++) {
            fieldCheck[i] = 0;
        }
        int x, y;
        outloop:
        for (x = n; x < n * 2 - 2; x++) {
            for (y = 0; y + x < fieldSize; y += fieldWidth) {
                if ((field[x + y] & 1) != 0) {
                    break outloop;
                }
            }
        }

        int x2 = n - x;
        for (int i = 0; i != fieldSize; i++) {
            x = (i + n - 2) % fieldWidth;
            y = (i + n - 2) / fieldWidth * n;
            if ((field[i] & 1) != 0) {
                fieldCheck[x + x2 + y] = 1;
            }
        }
        int of1;
        for (of1 = 0; of1 < fieldCheck.length && fieldCheck[of1] == 0; of1++){}
        boolean c = true;
        int r;
        for (r = 1; r < 4 && c; r++) {
            for (x = 0; x < n; x++) {
                for (y = 0; y < n; y++) {
                    int pos = rotationOffset[r] + rotationX[r] * x + rotationY[r] * y;
                    fieldCheckR[pos] = fieldCheck[x + y * n];
                }
            }
            int of2;
            for (of2 = 0; of2 < fieldCheckR.length && fieldCheckR[of2] == 0; of2++) {}
            of2 -= of1;
            int ed = (of2 > 0) ? (n * n - of2) : (n * n);
            for (int i = of1; i != ed; i++) {
                if (fieldCheck[i] > fieldCheckR[i + of2])
                    break;
                if (fieldCheck[i] < fieldCheckR[i + of2]) {
                    c = false;
                    break;
                }
            }

        }
       if (c) {
           result[lv]++;
       }
    }
}