Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.

Example 1:

Given nums = [1,1,1,2,2,3],

Your function should return length = 5, with the first five elements of nums being 1, 1, 2, 2 and 3 respectively.

It doesn't matter what you leave beyond the returned length.

Example 2:

Given nums = [0,0,1,1,1,1,2,3,3],

Your function should return length = 7, with the first seven elements of nums being modified to 0, 0, 1, 1, 2, 3 and 3 respectively.

It doesn't matter what values are set beyond the returned length.

 class Solution {

     public int removeDuplicates(int[] nums) {

         int m = 0;

         for (int i=0;i<nums.length;i++)

             if (m < 2 || nums[i] > nums[m-2])

                 nums[m++] = nums[i];

         return m;

     }

 }