Method idxToOri

app/src/main/java/solver/Utils.java:174–184

(int[] orientation, int index, int length, boolean zeroSum)

    }

    public static void idxToOri(int[] orientation, int index, int length, boolean zeroSum) {
        int sum = 0;
        int start = zeroSum ? length - 2 : length - 1;
        for (int i = start; i >= 0; i--) {
            orientation[i] = index % 3;
            index /= 3;
            sum += orientation[i];
        }
        if (zeroSum)
            orientation[length - 1] = 3 - sum % 3;
    }

    // combinations
    public static int combToIdx(int[] comb, int k, int n) {