Data Stream Median

public class Solution {
    /**
     * @param nums: A list of integers.
     * @return: the median of numbers
     */
    public int[] medianII(int[] nums) {
        int[] result = new int[nums.length];
        
        PriorityQueue<Integer> min = new PriorityQueue<Integer>();
        PriorityQueue<Integer> max = new PriorityQueue<Integer>(10, Collections.reverseOrder());
        
        for (int i = 0; i < nums.length; i++) {
            if (max.isEmpty() || nums[i] < max.peek()) {
                max.offer(nums[i]);
            } else {
                min.offer(nums[i]);
            }
            if (min.size() > max.size()) {
                max.offer(min.poll());
            }
            if (max.size() > min.size() + 1) {
                min.offer(max.poll());
            }
            result[i] = max.peek();
        }
        return result;
    }
}

public class Solution {
    /**
     * @param nums: A list of integers.
     * @return: the median of numbers
     */
    public int[] medianII(int[] nums) {
        // write your code here
        int[] result = new int[nums.length];
        for (int i = 0; i < nums.length; i++) {
            result[i] = helper(nums, 0, i, i / 2 + 1);
        }
        return result;
    }
        
    public int helper(int[] nums, int start, int end, int med) {
        int lo = start, hi = end, pivot = end;
        while (lo <= hi) {
            while (lo <= hi && nums[hi] >= nums[pivot]) hi --;
            while (lo <= hi && nums[lo] < nums[pivot]) lo ++;
            if (lo < hi) {
                swap(nums, lo, hi);
                lo ++;
                hi --;
            }
        }
        swap(nums, lo, pivot);
        if (med == lo + 1) {
            return nums[lo];
        } else if (med > lo + 1) {
            return helper(nums, lo + 1, end, med);
        } else {
            return helper(nums, start, lo - 1, med);
        }
    }
    public void swap(int[] nums, int a, int b) {
        int temp = nums[a];
        nums[a] = nums[b];
        nums[b] = temp;
    }
}