#305 Longest Common Subsequence

medium
javascript
blind75
dynamic-programming
string

Given two strings text1 and text2, find the length of their longest common subsequence.

Rules:

  • Subsequence can skip characters (doesn't need to be contiguous)
  • Must maintain relative order of characters
  • Common subsequence must exist in both strings
  • Return 0 if no common subsequence exists

Constraints:

  • 1 ≤ text1.length, text2.length ≤ 1000
  • Strings contain only lowercase English letters

Examples:

// Example 1:

console.log(longestCommonSubsequence("cat", "crabt"));
// Output: 3

// Explanation: "cat" is common subsequence


// Example 2:

console.log(longestCommonSubsequence("abcd", "abcd"));
// Output: 4

// Explanation: Entire string is common


// Example 3:

console.log(longestCommonSubsequence("abcd", "efgh"));
// Output: 0

// Explanation: No common subsequence