element x;
int count ← 0;
For(i = 0 to n − 1) {
  if(count == 0) { x ← A[i]; count++; }
  else if (A[i] == x) count++;
  else count−−;
}
Check if x is dominant element by scanning array A

static int dominant(final int... set) {
  final int[] freqs = new int[Integer.MAX_VALUE];
  for (int n : set) {
    ++freqs[n];
  }
  int dom_freq = Integer.MIN_VALUE;
  int dom_idx = -1;
  int dom_n = -1;
  for (int i = set.length - 1; i >= 0; --i) {
    final int n = set[i];
    if (dom_n != n) {
      final int freq = freqs[n];
      if (freq > dom_freq) {
        dom_freq = freq;
        dom_n = n;
        dom_idx = i;
      } else if (freq == dom_freq) {
        dom_idx = -1;
      }
    }
  }
  return dom_idx;
}

public int dominator(int[] A) {
    int N = A.length;

    for(int i = 0; i< N/2+1; i++)
    {
        int count=1;
        for(int j = i+1; j < N; j++)
        {
            if (A[i]==A[j]) {count++; if (count > (N/2)) return i;}
        }
    }

    return -1;
  }

public Integer findDominator(int[] arr) {
    int[] arrCopy = arr.clone();

    Arrays.sort(arrCopy);

    int length = arrCopy.length;
    int middleIndx = (length - 1) /2;

    int middleIdxRight;
    int middleIdxLeft = middleIndx;

    if (length % 2 == 0) {
        middleIdxRight = middleIndx+1;
    } else {
        middleIdxRight = middleIndx;
    }

    if (arrCopy[0] == arrCopy[middleIdxRight]) {
        return arrCopy[0];
    }

    if (arrCopy[middleIdxLeft] == arrCopy[length -1]) {
        return arrCopy[middleIdxLeft];
    }

    return null;
}