Interview Course Based on Story Questions

# Problem statement

You are given an `m x n` matrix. You have to return the length of the longest increasing path in this matrix.

From each cell, you can move in any one of four directions: _left, right, up, or down_. You may not move diagonally or move outside the matrix’s boundaries.

## Input

The input will be an `m x n` matrix of integers. The following is an example input:


```python
matrix = [
[3,4,5],
[3,2,6],
[2,2,1]
]
```

## Output

The output will be an integer value representing the longest path. The following is an example output for the above input:


```python
4
```

The longest increasing path with required constraints, comes out to be  `[3, 4, 5, 6]`.

# Coding exercise

Implement the  `longest_increasing_path(matrix)` function, where `matrix` is the `m x n` matrix of integers. The function will return a single integer value representing the number of cells in the longest path.


DIY: Longest Increasing Path in a Matrix

Problem statement