3 files changed, 105 insertions, 0 deletions
diff --git a/AlgoDesignAndTechniqueEdxJava/sources/LCS2.java b/AlgoDesignAndTechniqueEdxJava/sources/LCS2.java
new file mode 100644
index 0000000..d214eff
--- /dev/null
+++ b/AlgoDesignAndTechniqueEdxJava/sources/LCS2.java
@@ -0,0 +1,69 @@
+import java.util.Scanner;
+
+public class LCS2 {
+
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+        int n = scanner.nextInt();
+        int[] a = new int[n];
+        for (int i = 0; i < n; i++) {
+            a[i] = scanner.nextInt();
+        }
+
+        int m = scanner.nextInt();
+        int[] b = new int[m];
+        for (int i = 0; i < m; i++) {
+            b[i] = scanner.nextInt();
+        }
+
+        System.out.println(lcs2(a, b));
+    }
+
+    public static int[][] editDistance(int[] A, int[] B) {
+        int m = B.length;
+        int n = A.length;
+        int[][] D = new int[n + 1][m + 1];
+
+        for (int i = 0; i < n + 1; i++) {
+            D[i][0] = i;
+        }
+        for (int j = 0; j < m + 1; j++) {
+            D[0][j] = j;
+        }
+
+        for (int j = 1; j < m + 1; j++) {
+            for (int i = 1; i < n + 1; i++) {
+                int insertion = D[i][j - 1] + 1;
+                int deletion = D[i - 1][j] + 1;
+                int match = D[i - 1][j - 1];
+                int mismatch = D[i - 1][j - 1] + 1;
+                if (A[i - 1] == B[j - 1]) {
+                    D[i][j] = Math.min(insertion, Math.min(deletion, match));
+                } else {
+                    D[i][j] = Math.min(insertion, Math.min(deletion, mismatch));
+                }
+            }
+        }
+
+        return D;
+    }
+
+    public static int lcs2(int[] a, int[] b) {
+        int D[][] = editDistance(a, b);
+        return lcs2(a.length, b.length, D);
+    }
+
+    private static int lcs2(int i, int j, int[][] D) {
+        if (i == 0 && j == 0)
+            return 0;
+        if (i > 0 && D[i][j] == D[i - 1][j] + 1)
+            return lcs2(i - 1, j, D);
+        if (j > 0 && D[i][j] == D[i][j - 1] + 1)
+            return lcs2(i, j - 1, D);
+        else if (D[i][j] == D[i - 1][j - 1])
+            return 1 + lcs2(i - 1, j - 1, D);
+        else
+            return lcs2(i - 1, j - 1, D);
+    }
+
+}
diff --git a/AlgoDesignAndTechniqueEdxJava/tests/EditDistanceTest.java b/AlgoDesignAndTechniqueEdxJava/tests/EditDistanceTest.java
index 8c10432..e22ed87 100644
--- a/AlgoDesignAndTechniqueEdxJava/tests/EditDistanceTest.java
+++ b/AlgoDesignAndTechniqueEdxJava/tests/EditDistanceTest.java
@@ -7,6 +7,7 @@ class EditDistanceTest {
     @Test
     void test() {
         assertEquals(0, EditDistance.editDistance("ab", "ab"));
+        assertEquals(1, EditDistance.editDistance("a", "x"));
     }
 
     @Test
diff --git a/AlgoDesignAndTechniqueEdxJava/tests/LCS2Test.java b/AlgoDesignAndTechniqueEdxJava/tests/LCS2Test.java
new file mode 100644
index 0000000..bdfa799
--- /dev/null
+++ b/AlgoDesignAndTechniqueEdxJava/tests/LCS2Test.java
@@ -0,0 +1,35 @@
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class LCS2Test {
+
+    @Test
+    void test() {
+        int[] a = {2, 7, 5};
+        int[] b = {2, 5};
+        assertEquals(2, LCS2.lcs2(a,b));
+    }
+
+    @Test
+    void test1() {
+        int[] a = {7};
+        int[] b = {1, 2, 3, 4};
+        assertEquals(0, LCS2.lcs2(a,b));
+    }
+
+    @Test
+    void test2() {
+        int[] a = {2, 7, 8, 3};
+        int[] b = {5, 2, 8, 7};
+        assertEquals(2, LCS2.lcs2(a,b));
+    }
+
+    @Test
+    void test3() {
+        int[] a = {1, 2, 3, 4, 5, 6, 7};
+        int[] b = {1, 2, 8, 4, 5, 6};
+        assertEquals(5, LCS2.lcs2(a,b));
+    }
+
+}