26. Remove Duplicates from Sorted Array

Description:

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.

解题思路：大致意思是说给一个已经排序的数组，把其中重复的元素去掉，并返回数组的长度。对于这一类问题可以用两个指针，一个指针遍历整个数组，一个指针指向当前的不重复的元素。当发现下一个不重复的元素时，就将它复制到慢指针的后面即可。最后返回的慢指针也能记录数组的长度。

class Solution {public:    int removeDuplicates(vector<int>& nums) {        int length=nums.size();        if(length==0) return 0;        int index=0;        for(int i=0;i<length;i++){            if(nums[i]!=nums[index]){                nums[index+1]=nums[i];                index++;            }        }        return index+1;    }};