# 26. Remove Duplicates From Sorted Array 有序数组中去除重复项

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 by modifying the input array in-place with O(1) extra memory.

Example:

``````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 new length.
``````

Difficulty: Easy

### 解法1

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

###解法2

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