26.remove-duplicates-from-sorted-array.cs

/*
 * @lc app=leetcode id=26 lang=csharp
 *
 * [26] Remove Duplicates from Sorted Array
 *
 * https://leetcode.com/problems/remove-duplicates-from-sorted-array/description/
 *
 * algorithms
 * Easy (44.40%)
 * Likes:    2431
 * Dislikes: 4984
 * Total Accepted:    950.2K
 * Total Submissions: 2.1M
 * Testcase Example:  '[1,1,2]'
 *
 * Given a sorted array nums, remove the duplicates in-place such that each
 * element appear only once and return the new length.
 *
 * Do not allocate extra space for another array, you must do this by modifying
 * the input array in-place with O(1) extra memory.
 *
 * Example 1:
 *
 *
 * Given nums = [1,1,2],
 *
 * Your function should return length = 2, with the first two elements of nums
 * being 1 and 2 respectively.
 *
 * It doesn't matter what you leave beyond the returned length.
 *
 * Example 2:
 *
 *
 * Given nums = [0,0,1,1,1,2,2,3,3,4],
 *
 * Your function should return length = 5, with the first five elements of nums
 * being modified to 0, 1, 2, 3, and 4 respectively.
 *
 * It doesn't matter what values are set beyond the returned length.
 *
 *
 * Clarification:
 *
 * Confused why the returned value is an integer but your answer is an array?
 *
 * Note that the input array is passed in by reference, which means
 * modification to the input array will be known to the caller as well.
 *
 * Internally you can think of this:
 *
 *
 * // nums is passed in by reference. (i.e., without making a copy)
 * int len = removeDuplicates(nums);
 *
 * // any modification to nums in your function would be known by the caller.
 * // using the length returned by your function, it prints the first len
 * elements.
 * for (int i = 0; i < len; i++) {
 * print(nums[i]);
 * }
 */
namespace _26
{

    // @lc code=start
    public class Solution
    {
        public int RemoveDuplicates(int[] nums)
        {
            if (nums.Length < 2)
            {
                return nums.Length;
            }
            int j = 1;
            var prev = nums[0];
            for (int i = 1; i < nums.Length; i++)
            {
                if (prev != nums[i])
                {
                    nums[j++] = nums[i];
                    prev = nums[i];
                }
            }
            return j;
        }
        // public int RemoveDuplicates(int[] nums)
        // {
        //     var end = nums.Length > 1 ? 1 : nums.Length;
        //     for(int i = 1; i < nums.Length; i++)
        //         if(nums[i - 1] != nums[i])
        //             nums[end++] = nums[i];
        //     return end;
        // }
    }
    // @lc code=end
}