removeDuplicatesfromSortedArray.js

//////////////////////////////////////////////Remove Duplicates from Sorted Array///////////////////////////////////////////////////////
// Given an integer array nums sorted in non-decreasing order, remove the duplicates in-place such that each unique element
// appears only once. The relative order of the elements should be kept the same.
// Since it is impossible to change the length of the array in some languages, you must instead have the result be placed
// in the first part of the array nums. More formally, if there are k elements after removing the duplicates, then the first
// k elements of nums should hold the final result. It does not matter what you leave beyond the first k elements.
// Return k after placing the final result in the first k slots of nums.
// Do not allocate extra space for another array. You must do this by modifying the input array in-place with O(1) extra memory.
// Custom Judge:
// The judge will test your solution with the following code:
// int[] nums = [...]; // Input array
// int[] expectedNums = [...]; // The expected answer with correct length
// int k = removeDuplicates(nums); // Calls your implementation
// assert k == expectedNums.length;
// for (int i = 0; i < k; i++) {
//     assert nums[i] == expectedNums[i];
// }
// If all assertions pass, then your solution will be accepted.
// Example 1:
//
// Input: nums = [1,1,2]
// Output: 2, nums = [1,2,_]
// Explanation: Your function should return k = 2, with the first two elements of nums being 1 and 2 respectively.
// It does not matter what you leave beyond the returned k (hence they are underscores).
// Example 2:
//
// Input: nums = [0,0,1,1,1,2,2,3,3,4]
// Output: 5, nums = [0,1,2,3,4,_,_,_,_,_]
// Explanation: Your function should return k = 5, with the first five elements of nums being 0, 1, 2, 3, and 4 respectively.
// It does not matter what you leave beyond the returned k (hence they are underscores).
const removeDuplicates = function(nums) {
    if (nums.length <= 1) return nums.length;

    let l1 = 0, l2 = 1;
    while (l2 <= nums.length - 1) {
        if (nums[l2] !== nums[l1]) {
            nums[l1 + 1] = nums[l2];
            l1++;
        }
        l2++;
    }

    nums.splice(l1 + 1);

    return nums.length;
};

// console.log(removeDuplicates([1,1,2]));
// console.log(removeDuplicates([0,0,1,1,1,2,2,3,3,4]));