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# 26 Remove Duplicates from Sorted Array

## 26. [Remove Duplicates from Sorted Array](https://leetcode.com/problems/remove-duplicates-from-sorted-array/description/)

## 1. Question

Given a sorted array, remove the duplicates [**in-place**](https://en.wikipedia.org/wiki/In-place_algorithm) 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**](https://en.wikipedia.org/wiki/In-place_algorithm) 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.
```

## 2. Implementation

```java
class Solution {
    public int removeDuplicates(int[] nums) {
        if (nums.length < 2) {
            return nums.length;
        }

        int index = 1;
        for (int i = 1; i < nums.length; i++) {
            if (nums[i - 1] != nums[i]) {
                nums[index++] = nums[i];
            }
        }
        return index;
    }
}
```

## 3. Time & Space Complexity

时间复杂度O(n), 空间复杂度O(1)