/*LongestCommonSubsequence.java

Longest Common Subsequence

Given two strings, find the longest common subsequence (LCS).

Your code should return the length of LCS.

Example

For "ABCD" and "EDCA", the LCS is "A" (or "D", "C"), return 1.

For "ABCD" and "EACB", the LCS is "AC", return 2.

Clarification

What's the definition of Longest Common Subsequence?

•https://en.wikipedia.org/wiki/Longest_common_subsequence_problem

•http://baike.baidu.com/view/2020307.htm

Tags LintCode Copyright Longest Common Subsequence Dynamic Programming

*/

public class LongestCommonSubsequence {

/**

* @param A, B: Two strings.

* @return: The length of longest common subsequence of A and B.

*/

public int longestCommonSubsequence(String A, String B) {

// write your code here

if (A == null || A.length() == 0 || B == null || B.length() == 0) {

return 0;

}

int[][] lengthofLCS = new int[A.length() + 1][B.length() + 1];

for (int i = 1; i <= A.length(); i++) {

for (int j = 1; j <= B.length(); j++) {

lengthofLCS[i][j] = Math.max(lengthofLCS[i - 1][j], lengthofLCS[i][j - 1]);

if (A.charAt(i - 1) == B.charAt(j - 1)) {

lengthofLCS[i][j] = lengthofLCS[i - 1][j - 1] + 1;

}

}

}

return lengthofLCS[A.length()][B.length()];

}

public static void main(String[] args) {

LongestCommonSubsequence test = new LongestCommonSubsequence();

int result = test.longestCommonSubsequence("abbaisgreast", "test");

System.out.println("Expected: est");

System.out.println(result);

}

}