0026-remove-duplicates-from-sorted-array.js

/**
 * 26. Remove Duplicates from Sorted Array
 * https://leetcode.com/problems/remove-duplicates-from-sorted-array/
 * Difficulty: Easy
 *
 * 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.
 */

/**
 * @param {number[]} nums
 * @return {number}
 */
var removeDuplicates = function(nums) {
  let i = 0;
  for (let j = 0; j < nums.length; j++) {
    if (nums[i] !== nums[j]) {
      nums[++i] = nums[j];
    }
  }
  return ++i;
};

// var removeDuplicates = function(nums) {
//   let k = 0;
//   for (let i = 0; i < nums.length; i++) {
//     if (nums[k] !== nums[i]) {
//       k=k+1
//       nums[k] = nums[i];
//     }
//   }
//   return k+1;
// };