> For the complete documentation index, see [llms.txt](https://anton-veselskyi.gitbook.io/codding-problems-solutions/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://anton-veselskyi.gitbook.io/codding-problems-solutions/leetcode/easy/intersection-of-two-arrays-ii.md).

# Intersection of Two Arrays II

## [Intersection of Two Arrays II](https://leetcode.com/problems/intersection-of-two-arrays-ii)

Given two arrays, write a function to compute their intersection.

**Example 1:**

```

Input: nums1 = [1,2,2,1], nums2 = [2,2]
Output: [2,2]
```

**Example 2:**

```

Input: nums1 = [4,9,5], nums2 = [9,4,9,8,4]
Output: [4,9]
```

**Note:**

* Each element in the result should appear as many times as it shows in both arrays.
* The result can be in any order.

**Follow up:**

* What if the given array is already sorted? How would you optimize your algorithm?
* What if nums1's size is small compared to nums2's size? Which algorithm is better?
* What if elements of nums2 are stored on disk, and the memory is limited such that you cannot load all elements into the memory at once?

## Solutions

### 🧠 Cpp

```cpp
#include <algorithm>
using std::count;

class Solution
{
public:
    vector<int> intersect(vector<int>& nums1, vector<int>& nums2)
    {
        bool is_firstbigger = nums1.size() > nums2.size();
        vector<int> res,
            &big = is_firstbigger ? nums1 : nums2,
            &small = is_firstbigger ? nums2 : nums1;



        for(int i = 0; i < small.size(); ++i)
        {
            int b_element = small[i],  
                count_in_big = count(big.begin(), big.end(), b_element);

            if(count_in_big > 0 && count(res.begin(), res.end(), b_element) == 0)
            {
                int count_in_small = count(small.begin(), small.end(), b_element);
                res.insert(res.begin(), std::min(count_in_big, count_in_small), b_element);
            }   
        }

        return res;
    }
};
```


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://anton-veselskyi.gitbook.io/codding-problems-solutions/leetcode/easy/intersection-of-two-arrays-ii.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.