Java LCS lcs3(int[] A, int[] B)

Description

lcs

License

Apache License

Declaration

public static int lcs3(int[] A, int[] B) 

Method Source Code

//package com.java2s;
/*//from w w w. j av a2s . c o  m
 * org.fsola
 *
 * File Name: LongestCommonSubsequence.java
 *
 * Copyright 2014 Dzhem Riza
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

public class Main {
    public static int lcs3(int[] A, int[] B) {
        int[][] M = new int[A.length][B.length];
        int[] S = new int[Math.max(A.length, B.length)];

        for (int i = 0; i < A.length; ++i) {
            for (int j = 0; j < B.length; ++j) {
                M[i][j] = -1;
            }
        }

        for (int i = 0; i < S.length; ++i) {
            S[i] = -1;
        }

        int r = lcs3impl(A, B, M, S, 0, 0);

        System.out.println("M:");
        for (int i = 0; i < A.length; ++i) {
            for (int j = 0; j < B.length; ++j) {
                System.out.print(" " + M[i][j]);
            }
            System.out.println();
        }

        // Print the LCS
        int start = -1;
        for (int i = S.length - 1; i > 0; --i) {
            if (S[i] != -1) {
                start = i;
                break;
            }
        }

        if (start != -1) {
            System.out.print("LCS:");
            for (int x = start; x >= 0; x = S[x]) {
                System.out.print(" " + A[x]);
            }
            System.out.println();
        }

        return r;
    }

    public static int lcs3impl(int[] A, int[] B, int[][] M, int[] S, int I, int J) {
        if (A.length <= I || B.length <= J) {
            return 0;
        }

        if (M[I][J] != -1) {
            return M[I][J];
        }

        int max = 0;
        for (int i = I; i < A.length; ++i) {
            for (int j = J; j < B.length; ++j) {
                if (A[i] == B[j]) {
                    int c = lcs3impl(A, B, M, S, i + 1, j + 1) + 1;

                    if (max < c) {
                        max = c;
                        S[i] = I - 1;
                    }
                }
            }
        }

        M[I][J] = max;

        return max;
    }
}

Related

1. lcs(String s1, String s2)
2. lcs(String str1, String str2)
3. lcs(String X, String Y, int m, int n)
4. lcs1(int[] A, int[] B)
5. lcs2(int[] A, int[] B, int m, int n)
6. lcs4(int[] A, int[] B)
7. LCSAlgorithm(String a, String b)
8. lcse(String str1, String str2)
9. LCSIterative(Character[] X, int i, Character Y[], int j, int c[][])