Longest Common Subsequence Using Recursive Method

LongestCommonSubsequence.java

import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

public class LongestCommonSubsequence {

    public static void main(String args[]) {
        long timestamp1 = System.currentTimeMillis();
        System.out.println("---------------Longest Common Subsequence Using Recursive Method-----------------");

        String string1 = "AGGTABNDSV";
        String string2 = "GXTXAYBDFGHOI";

        String longestCommonSubsequence = findLongestSubsequence(string1, string2);
        System.out.println("LCS is "+new StringBuilder(longestCommonSubsequence).reverse().toString());
        long timestamp2 = System.currentTimeMillis();
        System.out.println(" Time Taken : "+(timestamp2-timestamp1));
    }

    private static String findLongestSubsequence(String string1, String string2) {

        char[] charArray1 = string1.toCharArray();
        char[] charArray2 = string2.toCharArray();
        int arraylength1 = string1.length() - 1;
        int arraylength2 = string2.length() - 1;
        String longestCommonSubsequence = "";

        if (arraylength1 < 0 || arraylength2 < 0)
            return longestCommonSubsequence;


        String newStr1 = String.valueOf(Arrays.copyOfRange(charArray1, 0, arraylength1));
        String newStr2 = String.valueOf(Arrays.copyOfRange(charArray2, 0, arraylength2));

        if (charArray1[arraylength1] == charArray2[arraylength2]) {
            longestCommonSubsequence = longestCommonSubsequence + charArray1[arraylength1];
            longestCommonSubsequence = longestCommonSubsequence + findLongestSubsequence(newStr1, newStr2);
        } else {
            String res1 = findLongestSubsequence(newStr1, String.valueOf(charArray2));
            String res2 = findLongestSubsequence(String.valueOf(charArray1), newStr2);
            if (res1.length() > res2.length()) {
                longestCommonSubsequence = longestCommonSubsequence + res1;
            } else
                longestCommonSubsequence = longestCommonSubsequence + res2;
        }

        return longestCommonSubsequence;
    }
}