[LeetCode] String Reorder Distance Apart

Question:
Given a string of lowercase characters, reorder them such that the same characters are at least distance d from each other.

Input: { a, b, b }, distance = 2
Output: { b, a, b }

http://leetcode.com/2010/05/here-is-another-google-phone-interview.html

public void reorder(int[] A, int d)
{
// Stats
Map<Integer, Integer> map = new HashMap<>();
for (int i : A)
{
Integer occurance = map.get(i);
if (occurance == null)
occurance = 0;
occurance++;
map.put(i, occurance);
}

// Sort
List<Map.Entry<Integer, Integer>> list = new ArrayList<>(map.entrySet());
Collections.sort(list, new Comparator<Map.Entry<Integer, Integer>>()
{
public int compare(Entry<Integer, Integer> a, Entry<Integer, Integer> b)
{
return -1 * Integer.compare(a.getValue(), b.getValue());
}
});

// Re-assign
int curIndex = 0;
Map.Entry<Integer, Integer> cur = list.get(curIndex);
int curOccurance = 0;
for (int offset = 0; offset < d; offset++)
{
for (int i = offset; i < A.length; i += d)
{
A[i] = cur.getKey();
curOccurance++;

if (curOccurance == cur.getValue())
{
curIndex++;
if (curIndex == list.size())
return;
cur = list.get(curIndex);
curOccurance = 0;
}
}
}
}