DevGod needs to write a blog entry for this problem!

/**
 * @param {number[]} nums
 * @return {number}
 */
var removeDuplicates = function(nums) {
    let slow=0 ;

    for(let fast=0 ; fast<nums.length; fast++){
        if(nums[fast] !== nums[fast+2]){
            nums[slow] = nums[fast];
            slow++
        }
    }

    return slow;
};