text: /*
  Given a sorted array nums, remove the duplicates in-place such that duplicates appeared at most twice and return the new length.
  
  Do not allocate extra space for another array; you must do this by modifying the input array in-place with O(1) extra memory.
  
  Clarification:
  
  Confused why the returned value is an integer, but your answer is an array?
  
  Note that the input array is passed in by reference, which means a modification to the input array will be known to the caller.
  
  Internally you can think of this:
  
  // nums is passed in by reference. (i.e., without making a copy)
  int len = removeDuplicates(nums);
  
  // any modification to nums in your function would be known by the caller.
  // using the length returned by your function, it prints the first len elements.
  for (int i = 0; i < len; i++) {
      print(nums[i]);
  }
   
  
  Example 1:
  
  Input: nums = [1,1,1,2,2,3]
  Output: 5, nums = [1,1,2,2,3]
  Explanation: 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:
  
  Input: nums = [0,0,1,1,1,1,2,3,3]
  Output: 7, nums = [0,0,1,1,2,3,3]
  Explanation: 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.
   
  
  Constraints:
  
  1 <= nums.length <= 3 * 104
  -104 <= nums[i] <= 104
  nums is sorted in ascending order.
  */
  
  /**
   * @param {number[]} nums
   * @return {number}
   */
   var removeDuplicates = function(nums) {
      let validCount = 0;
      let currNumber, currCount;
      for(let i = 0; i < nums.length; i++){
          if(nums[i] !== currNumber){
              currNumber = nums[i];
              currCount = 1;
              validCount++;
          } else {
              if(currCount >= 2){
                  nums[i] = null;
              } else {
                  currCount++;
                  validCount++;
              }
          }
      }
      
      let position = 0;
      for(let i = 0; i < nums.length; i++){
          if(nums[i] !== null){
              [nums[i], nums[position]] = [nums[position], nums[i]];
              position++;
          }
      }
      
      return validCount;
  };