public void removeZeros(int[] data) {
    int zeroIdx = data.size() - 1;
    int zeroNum = 0;
    for (int i = 0; i < data.size(); i++) {
        int idx = i;
        while (data[idx] == 0) {
            zeroNum++;
        }
        if ((i + zeroNum) < data.size()) {
            data[i] = data[i + zeroNum];
        }
    }
    return data.size() - zeroNum;
}

// 0 0
// 1


// 1 2 3 4 5
// 2
// x = a[i] + a[j]
//&& (data[idx] == y)
public int[] findIdx(int[] data, int sum) {
    Arrays.sort(data);
    int[] ans = new int[2];
    for (int i = 0; i < data.size(); i++) {
        int x = data[i];
        int y = sum - data[i];
        int idx = Arrays.binarySearch(data, y);
        ans[0] = -1;
        ans[1] = -1;
        if ((idx > -1) && (idx < data.size())  && (i != idx)) {
            ans[0] = i;
            ans[1] = idx;
        }

    }
    return ans;
}