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# 1143. Longest Common Subsequence

## Medium

***

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.

 

**Example 1:**

<pre><code>Input: text1 = "abcde", text2 = "ace" 
<strong>Output:
</strong> 3  
<strong>Explanation:
</strong> The longest common subsequence is "ace" and its length is 3.
</code></pre>

**Example 2:**

<pre><code>Input: text1 = "abc", text2 = "abc"
<strong>Output:
</strong> 3
<strong>Explanation:
</strong> The longest common subsequence is "abc" and its length is 3.
</code></pre>

**Example 3:**

<pre><code>Input: text1 = "abc", text2 = "def"
<strong>Output:
</strong> 0
<strong>Explanation:
</strong> There is no such common subsequence, so the result is 0.
</code></pre>

&#x20;

**Constraints:**

* `1 <= text1.length, text2.length <= 1000`
* `text1` and `text2` consist of only lowercase English characters.