(Leetcode)sort-array by parity-ii,Javaプール

public int[] sortArrayByParityII(int[] nums) {
        int size = 0;
        if (nums.length % 2 == 0) {
            size = nums.length / 2;
        } else {
            size = nums.length / 2 + 1;
        }
        //int[] odd = new int[size];
        //int[] evn = new int[size];
        List<Integer> odd = new ArrayList<>();
        List<Integer> evn = new ArrayList<>();

        int eIdx = 0, oIdx = 0;
        for (int i : nums) {
            if (i % 2 == 0) {
                //evn[eIdx++] = i;
                evn.add(i);
            } else {
                //odd[oIdx++] = i;
                odd.add(i);
            }
        }


        Collections.sort(odd, Collections.reverseOrder());
        Collections.sort(evn, Collections.reverseOrder());

        int[] answer = new int[nums.length];

        for (int i = 0; i < nums.length; i++) {
            if (i % 2 == 0) {
                answer[i] = evn.get(i / 2);
            } else {
                answer[i] = odd.get(i / 2);
            }

        }
        return answer;
    }