Longest Common Subsequence Length
Problem Description
Given two strings `textA` and `textB`, return the length of their **longest common subsequence** (LCS).
A **subsequence** is a sequence derived from a string by deleting zero or more characters without changing the relative order of the remaining characters. A **common subsequence** is one that is a subsequence of both strings.
If there is no common subsequence, return `0`.
**Example 1:**
```
Input: textA = "carpet", textB = "apart"
Output: 4
Explanation: "aprt" is a common subsequence of length 4.
```
**Example 2:**
```
Input: textA = "flight", textB = "fright"
Output: 5
Explanation: "fIght" → "fight" is a common subsequence of length 5.
```
Constraints
- 1 <= textA.length, textB.length <= 1000
- textA and textB consist of lowercase English letters only
Follow-up
Can you reconstruct and return the actual longest common subsequence string, not just its length?
Hints
Try the problem first. If you get stuck, you can reveal hints one at a time.
Solution
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