Given a non-empty integer array, find the minimum number of moves required to make all array elements equal, where a move is incrementing a selected element by 1 or decrementing a selected element by 1.

You may assume the array’s length is at most 10,000.

Example:

Input:
[1,2,3]

Output:
2

Explanation:
Only two moves are needed (remember each move increments or decrements one element):

[1,2,3]  =>  [2,2,3]  =>  [2,2,2]

思路：
要寻找最后所有数字都是一样的那个数字N。 为了移动的次数最小，显然应该是中位数。

class Solution
    public int minMoves2(int[] nums) {
        if(nums == null || nums.length ==0) 
            return 0;

        Arrays.sort(nums);
        int median = nums[nums.length/2];
        int sum = 0;
        for(int i = 0;i < nums.length;i++){
            sum += Math.abs(nums[i] - median);
        }
        return sum;
    }
}