Longest Common Subsequence
Given two strings word1 and word2, determine the length of the longest common subsequence between the two strings.
A subsequence consists of characters from the original string that appear in the same order but may not be consecutive. For instance, "ace" is a valid subsequence of "abcde", but "aec" is not. More formally, a subsequence of a string is derived by deleting zero or more characters from the original string, without altering the relative order of the remaining characters.
A common subsequence of two strings is a string that is a subsequence of both strings.
If the two strings share no common subsequences, the answer is 0.
Example 1:
Input:
word1 = "abcde" word2 = "ace"
Output: 3
Explanation:
The longest common subsequence is ace and its length is 3.
Example 2:
Input:
word1 = "almost" word2 = "algomonster"
Output: 6
Explanation:
The longest common subsequence is almost and its length is 6.
Example 3:
Input:
word1 = "abc" word2 = "def"
Output: 0
Explanation:
There is no such common subsequence, so the result is 0.