class Solution {
    public int[] sortArrayByParity(int[] A) {
        int i = 0;
        int j = A.length - 1;
        int[] result = new int[A.length];

        for(int x : A) {
            if (x % 2 == 0) {
                result[i++] = x;
            } else {
                result[j--] = x;
            }
        }
        return result;
    }
}