26.删除有序数组中的重复项

双指针

时间复杂度$O(n)$

空间复杂度$O(1)$

class Solution {
    public int removeDuplicates(int[] nums) {
        int left = 0, right = 1, n = nums.length;
        while (right < n) {
            if (nums[right] != nums[left]) {
                left++;
                nums[left] = nums[right];
            }
            right++;
        }
        return left + 1;
    }
}