In this tutorial, you will learn how the longest common subsequence is found. Also, you will find working examples of the longest common subsequence in C, C++, Java and Python.

The longest common subsequence (LCS) is defined as the longest subsequence that is common to all the given sequences, provided that the elements of the subsequence are not required to occupy consecutive positions within the original sequences.

If S1 and S2 are the two given sequences then, Z is the common subsequence of S1 and S2 if Z is a subsequence of both S1 and S2. Furthermore, Z must be a strictly increasing sequence of the indices of both S1 and S2.

In a strictly increasing sequence, the indices of the elements chosen from the original sequences must be in ascending order in Z.

Reference:

https://www.youtube.com/watch?v=ASoaQq66foQ https://www.programiz.com/dsa/longest-common-subsequence