26. Remove Duplicates from Sorted Array

Given a sorted array, 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 in place with constant memory.

For example,
Given input array 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 new length.

思路: 两个指针，后面一个指针用来找不一样的，前一个用来记录unique的位置，后面找到一个不一样的，就放到前面的下一个位置。

class Solution {public:    int removeDuplicates(vector<int>& nums) {        if (nums.size() <= 1)        {            return nums.size();        }        int i = 0, j = 1;        while (j < nums.size())        {            if (nums[i] == nums[j])            {                j++;            }            else            {                i++;                nums[i] = nums[j];                j++;            }        }        return i + 1;    }};