[Array] 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.

方法：利用数组已经有序这个条件，然后再采用两个指针(two pointer)的方法进行。

class Solution {
public:
    int removeDuplicates(vector<int>& nums) {

        int i=0;
        for(int j=1;j<nums.size();j++)
            if(nums[j]!=nums[i])
                nums[++i]=nums[j];

        return nums.size()==0?0:i+1;
    }
};