Java LCS LCS(String a, String b)

Description

LCS

License

Open Source License

Declaration

public static int LCS(String a, String b) 

Method Source Code

//package com.java2s;
//License from project: Open Source License 

public class Main {
    static int dp[][];

    public static int LCS(String a, String b) {
        int Rows = a.length() + 1;
        int Cols = b.length() + 1;
        dp = new int[Rows][Cols];
        for (int i = 0; i <= a.length(); i++) {
            dp[i][0] = 0;/*w  w w . j  a v a 2  s  .  co  m*/
        }
        for (int i = 0; i <= b.length(); i++) {
            dp[0][i] = 0;
        }

        for (int i = 1; i <= a.length(); i++) {
            for (int j = 1; j <= b.length(); j++) {
                if (i == 0 || j == 0) {
                    dp[i][j] = 0;
                } else if (a.charAt(i - 1) == b.charAt(j - 1)) {
                    dp[i][j] = 1 + dp[i - 1][j - 1];
                } else {
                    dp[i][j] = Math.max(dp[i - 1][j], dp[i][j - 1]);
                }
            }
        }
        System.out.println(backTrace(a, b, a.length(), b.length()));
        return dp[a.length()][b.length()];
    }

    public static String backTrace(String a, String b, int i, int j) {
        if (i == 0 || j == 0)
            return "";
        else if (a.charAt(i - 1) == b.charAt(j - 1))
            return backTrace(a, b, i - 1, j - 1) + a.charAt(i - 1);
        else {
            if (dp[i][j - 1] > dp[i - 1][j])
                return backTrace(a, b, i, j - 1);
            else
                return backTrace(a, b, i - 1, j);
        }

    }
}

Related

1. lcs(char[] A, char[] B)
2. lcs(char[] inputString1, char[] inputString2, int length1, int length2)
3. LCS(String A, String B)
4. lcs(String a, String b)
5. lcs(String a, String b)
6. lcs(String arg0, String arg1)