Initial commit

lab_3/main.java

@@ -0,0 +1,57 @@
+package lab_3;
+
+public class main {
+    static int maxStrLength;
+    static String result;
+    
+    public static void cSubUtil(StringBuilder stringbuilder, int leftBoundary, int rightBoundary) {
+        String string = stringbuilder.toString().toLowerCase().replaceAll("[^a-z]","");
+        // check if the indices lie in the range of string
+        // and also if it is palindrome
+        while (leftBoundary >= 0 && rightBoundary < string.length() && string.toLowerCase().charAt(leftBoundary) == string.toLowerCase().charAt(rightBoundary)) {
+            // expand the boundary
+            leftBoundary--;
+            rightBoundary++;
+        }
+        // if it's length is greater than maxStrLength update
+        // maxLength and result
+        if (rightBoundary - leftBoundary - 1 >= maxStrLength) {
+            result = string.substring(leftBoundary + 1, rightBoundary);
+            maxStrLength = rightBoundary - leftBoundary - 1;
+        }
+    }
+
+    public static int longestPalSubstr(StringBuilder string)
+    {
+        result = "";
+        maxStrLength = 1;
+        // for every index in the string check palindromes
+        // starting from that index
+        for (int i = 0; i < string.length(); i++) {
+            // check for odd length palindromes
+            cSubUtil(string, i, i);
+            // check for even length palindromes
+            cSubUtil(string, i, i + 1);
+        }
+        System.out.println("Longest palindrome substring is: " + compareStrings(string));
+        return compareStrings(string).length();
+    }
+
+    public static String compareStrings(StringBuilder builder) {
+        for (int leftBoundary = 0; leftBoundary <= builder.length(); leftBoundary++) {
+            for (int rightBoundary = builder.length(); rightBoundary >= leftBoundary; rightBoundary--) {
+                if (result.equals(builder.substring(leftBoundary, rightBoundary).toLowerCase().replaceAll("[^a-z]",""))) {
+                    return builder.substring(leftBoundary, rightBoundary);
+                }
+            }
+        }
+        return "";
+    }
+
+    public static void main(String[] args) {
+        StringBuilder stringToDetect = new StringBuilder("Eva, can I see bees in a cave?");
+
+        System.out.println("Initial string: " + stringToDetect);
+        System.out.println("Length is: " + longestPalSubstr(stringToDetect));
+    }
+}