The Blind 75 Leetcode Series: Longest Common Subsequence

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1143. Longest Common Subsequence

Given two strings text1 and text2, return the length of their longest common subsequence. If there is no common subsequence, return 0.

A subsequence of a string is a new string generated from the original string with some characters (can be none) deleted without changing the relative order of the remaining characters.

For example, "ace" is a subsequence of "abcde".

A common subsequence of two strings is a subsequence that is common to both strings.

We are given 2 strings. There can be some letters existing in both strings with same order. We want to see what’s the longest common subsequence we can find in these strings. Note that a subsequence is only valid if the orders do not change. This means we cannot rearrange the letters.

A few questions to ask before diving into the problem:

1. are we only looking at lowercase alphabets like the examples present?
2. what’s the longest possible string we are going to see?
3. do common subsequences have to start from…