distinctDifferenceArray

class Solution {
    public int[] distinctDifferenceArray(int[] nums) {
        int n = nums.length;
        int[] diff = new int[n];
        for(int i=0;i<n;i++){
            HashMap<Integer, Integer> count1 = new HashMap<Integer, Integer>();
            HashMap<Integer, Integer> count2 = new HashMap<Integer, Integer>();
            int[] suffix = new int[n-i-1];
            int[] prefix = new int[i+1];
            prefix = Arrays.copyOfRange(nums, 0, i+1);
            suffix = Arrays.copyOfRange(nums, i+1, n);
            for (int num : prefix) {
                count1.put(num, count1.getOrDefault(num, 0) + 1);
            }
            for (int num : suffix) {
                count2.put(num, count2.getOrDefault(num, 0) + 1);
            }
            int difPrefix = 0, difSuffix = 0;
            for(int key : count1.keySet()){
                if(count1.get(key) > 0)
                    difPrefix++;
            }
            for(int key : count2.keySet()){
                if(count2.get(key) > 0)
                    difSuffix++;
            }
            diff[i] = difPrefix - difSuffix;
        }
        return diff;
    }
}