feb 2015 problem 8

uil/aplus-february-2015/8/Name.java

@@ -0,0 +1,49 @@
+import static java.lang.System.out;
+import java.util.Scanner;
+import java.io.File;
+import java.io.IOException;
+
+class Main {
+    public static void main(String[] args) throws IOException {
+        Scanner s = new Scanner(new File("name.dat"));
+        while(s.hasNextLine()) {
+            String operation = s.next();
+            String input = s.next();
+            int right = s.nextInt();
+            int left = s.nextInt();
+
+            out.println(String.format(
+                "%s==>%s", input,
+                operation.equals("E") ? encrypt(input, right, left) : decrypt(input, right, left)
+            ));
+        }
+    }
+
+    public static String encrypt(String input, int right, int left) {
+        right = input.length() / right;
+        left = input.length() / left;
+        return leftCircle(rightCircle(reverse(input), right), left);
+    }
+
+    public static String decrypt(String input, int right, int left) {
+        right = input.length() - (input.length() / right);
+        left = input.length() - (input.length() / left);
+        return reverse(rightCircle(leftCircle(input, left), right));
+    }
+
+    public static String rightCircle(String input, int right) {
+        return input.substring(input.length() - right) + input.substring(0, input.length() - right);
+    }
+
+    public static String leftCircle(String input, int left) {
+        return input.substring(left, input.length()) + input.substring(0, left);
+    }
+
+    public static String reverse(String input) {
+        String result = "";
+        char[] arr = input.toCharArray();
+        for(int i = arr.length - 1; i >= 0; i--)
+            result += arr[i];
+        return result;
+    }
+}