Leetcode - 26. Remove Duplicates from Sorted Array

Trick is to know if a number is duplicate (seeing that num for first time) in a sorted array we just need to compare with the previous element

one point l -> takes care where u r going to update
other pointer r -> takes care of going through all numbers

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

    let l = 1 ;
    for ( let r = 1 ; r<nums.length;r++){
            if( nums[r] != nums[r-1]){
                nums[l] = nums[r];
                l++
            }
    }
    return l
};

Comments

[gesslar]

It would be helpful to mention that this is an in-place mutation. For a new array, the Set trick is pretty good. It is lovely, though.