# LeetCode — Longest Common Sequences

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:**

**Input:** text1 = "abcde", text2 = "ace"

**Output:** 3

**Explanation:** The longest common subsequence is "ace" and its length is 3.

**Example 2:**

**Input:** text1 = "abc", text2 = "abc"

**Output:** 3

**Explanation:** The longest common subsequence is "abc" and its length is 3.

**Example 3:**

**Input:** text1 = "abc", text2 = "def"

**Output:** 0

**Explanation:** There is no such common subsequence, so the result is 0.

**Constraints:**

`1 <= text1.length, text2.length <= 1000`

`text1`

and`text2`

consist of only lowercase English characters.

Solution:

Time Complexity:** O(n²)**

Space Complexity: **O(n²)**