Initial data commit

Task/Longest-common-substring/Java/longest-common-substring.java

@@ -0,0 +1,28 @@
+public class LongestCommonSubstring {
+
+    public static void main(String[] args) {
+        System.out.println(lcs("testing123testing", "thisisatest"));
+        System.out.println(lcs("test", "thisisatest"));
+        System.out.println(lcs("testing", "sting"));
+        System.out.println(lcs("testing", "thisisasting"));
+    }
+
+    static String lcs(String a, String b) {
+        if (a.length() > b.length())
+            return lcs(b, a);
+
+        String res = "";
+        for (int ai = 0; ai < a.length(); ai++) {
+            for (int len = a.length() - ai; len > 0; len--) {
+
+                for (int bi = 0; bi <= b.length() - len; bi++) {
+
+                    if (a.regionMatches(ai, b, bi, len) && len > res.length()) {
+                        res = a.substring(ai, ai + len);
+                    }
+                }
+            }
+        }
+        return res;
+    }
+}