# 27. Anti Diagonal Traversal of Matrix

The problem can be found at the following link: [Question Link](https://www.geeksforgeeks.org/problems/print-diagonally1623/1)

![](https://badgen.net/badge/Level/Medium/yellow)

## My Approach

To traverse the anti-diagonals of the matrix,

* I used a helper function `fill` that starts at a given position `(i, j)` and moves diagonally down until it reaches the border of the matrix.
* I called this `fill` function for the `top row` and `rightmost column` to cover all the anti-diagonals.

## Time and Auxiliary Space Complexity

* **Time Complexity**: `O(N*N)`, where N is the total number of rows and columns in the matrix. We visit each element exactly once.
* **Auxiliary Space Complexity**: `O(N*N)`, where N is the total number of rows and columns in the matrix. This is the space required to store the output vector.

## Code (C++)

```cpp
class Solution {
public:
    void fill(int i, int j, vector<vector<int>>& mat, vector<int>& out){
        while(i < mat.size() && j >= 0){
            out.push_back(mat[i][j]);
            ++i;
            --j;
        }
    }
    vector<int> antiDiagonalPattern(vector<vector<int>>& mat) 
    {
        vector<int> out;
        int n = mat.size();
        for(int j = 0; j < n; ++j)
            fill(0, j, mat, out);
        
        for(int i = 1; i < n; ++i)
            fill(i, n-1, mat, out);
        
        return out;
    }
};
```

## Contribution and Support

For discussions, questions, or doubts related to this solution, please visit our [discussion section](https://github.com/getlost01/gfg-potd/discussions). We welcome your input and aim to foster a collaborative learning environment.

If you find this solution helpful, consider supporting us by giving a `⭐ star` to the [getlost01/gfg-potd](https://github.com/getlost01/gfg-potd) repository.


---

# Agent Instructions: 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://gl01.gitbook.io/gfg-editorials/2023/12-2023-dec-26/27-anti-diagonal-traversal-of-matrix.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.