score function

int score() {
    int[] rowSum = new int[cubeSize];
    int[] colSum = new int[cubeSize];
    int d1 = 0;
    int d2 = 0;

    for(int j=0; j<cubeSize; j++) {
        for(int i=0; i<cubeSize; i++) {
            rowSum[j] += genotype[cubeSize*j + i];
            colSum[j] += genotype[cubeSize*i + j];
        }
    }

    for(int k=0; k<cubeSize; k++) {
        d1 += genotype[cubeSize*k + k];
        d2 += genotype[(cubeSize-k)*cubeSize - (cubeSize-k)];
    }

    int sumDifference = 0;
    for(int i=0; i<cubeSize; i++) {
        sumDifference += (magicSum - rowSum[i]) * (magicSum - rowSum[i]);
        sumDifference += (magicSum - colSum[i]) * (magicSum - colSum[i]);
    }

    sumDifference += (magicSum - d1) * (magicSum - d1);
    sumDifference += (magicSum - d2) * (magicSum - d2);

    return sumDifference;
}