Interview Course Based on Story Questions

# Problem statement
In this challenge, you will be given a list of strings that you need to find in the 2D grid. Neighboring characters can be combined to form strings. Remember that the diagonals are not included in neighboring characters; only *up*, *down*, *right*, and *left* neighbors can be considered. The solution should return a list containing the strings from the input list that were successfully found in the grid. To help you solve this problem, you will be provided with an implementation for the `Trie` class, which you can use to optimize your solution. 

## Input
The first input will be a 2D list, meaning a list of lists. The 2D list will represent the grid of characters. The second input will be a list of strings that need to be searched in the grid. The following is an example input:
```python3
[['C', 'O', 'L', 'I', 'M'], 
['I', 'N', 'L', 'M', 'O'], 
['A', 'L', 'I', 'E', 'O'], 
['R', 'T', 'A', 'S', 'N'], 
['S', 'I', 'T', 'A', 'C']]

["REINDEER", "IN", "RAIN"]
```


## Output
The output will be a list of strings containing the strings from the input list found in the grid. The following is an example output for the inputs above:
```python3
["IN", "RAIN"]
```
> The order of the strings in the output does not matter. 

# Coding exercise
You need to implement the `find_strings(grid, strings)` function, where the `grid` is a 2D array of characters and `strings` is the list of strings that we are searching for. The function returns a list of strings representing the strings that were found.

DIY: Word Search II

Problem statement