# Longest Common Substring Problem

The longest common substring problem is to find the longest string 
(or strings) that is a substring (or are substrings) of two or more 
strings.

## Example

The longest common substring of the strings `ABABC`, `BABCA` and 
`ABCBA` is string `ABC` of length 3. Other common substrings are
`A`, `AB`, `B`, `BA`, `BC` and `C`.

```
ABABC
  |||
 BABCA
  |||
  ABCBA
```

## References

- [Wikipedia](https://en.wikipedia.org/wiki/Longest_common_substring_problem)
- [YouTube](https://www.youtube.com/watch?v=BysNXJHzCEs&list=PLLXdhg_r2hKA7DPDsunoDZ-Z769jWn4R8)
