Given a sorted array, return n unique counts of elements in it, while also rearranging the array such that the first n element is unique. Diagram illustration as below
If you think the problem is confusing, you haven’t seen its crude form. Initially the problem was phrased as removing duplicates which is hella confusing.
Here is my code to this problem.
First we check if the nums array is empty, if it is, terminate the function by returning 0. If not, we initialize 2 variables, i and j. We then loop through the length of nums array. Let’s go over an example with our given array [0,0,1,1,2]. Here is what happens in the for loop:
i=0, j=1. Check if nums[0] is equal to nums[1]. True.
nums = [0,0,1,1,2]
i=0,j=2. Check if nums[0] is equal to nums[2]. False. =>increment i by 1. nums[1] = nums[2]. Note lists are mutable.
nums = [0,1,1,1,2]
i=1,j=3. Check if nums[1] is equal to nums[3]. True.
nums = [0,1,1,1,2]
i=1,j=4. Check if nums[1] is equal to nums[4]. False. =>increment i by 1. nums[2] = nums[4].
nums = [0,1,2,1,2]
We then return the count of i+1, since i started from 0. This is how we return the number of unique elements while reordering the array with no added memory.
Learn together, happy coding!
