Codility.com Demo Test

I like online programming challenges like this demo offered by Codility, it reassures me that I might still be able to think, check it out here:

Sample Test

This was my solution:

private static int equi(int[] A) {

  if (null == A) {
    return -1;
  }

  int size = A.length;

  if (size == 0) {
    return -1;
  }

  long runningSum = 0;
  long[] runningSums = new long[size];

  for (int i = 0; i < size; i++) {
    runningSum += A[i];
    runningSums[i] = runningSum;      
  }

  for (int i = 0; i < size; i++) {
    long lhsSum = runningSums[i] - A[i];
    long rhsSum = runningSum - runningSums[i];

    if(lhsSum == rhsSum) {
      return i;
    }
  }

  return -1;
}