ADD_BinarySearchHacker

src/BinarySearchHackerThread.java

+public class BinarySearchHackerThread extends Thread {
+    private Vault vault;
+    private int attempts;
+
+    public BinarySearchHackerThread(Vault vault) {
+        this.vault = vault;
+        this.setName("BinarySearchHacker");
+        this.setPriority(Thread.MAX_PRIORITY);
+        this.attempts = 0;
+    }
+
+    @Override
+    public void run() {
+        System.out.println(this.getName() + " started hacking with REAL binary search algorithm");
+
+        int low = 0;
+        int high = 9999;
+
+        while (low <= high) {
+            attempts++;
+            int mid = low + (high - low) / 2;
+
+            int result = vault.comparePassword(mid);
+
+            if (result == 0) {
+                // Password is true
+                System.out.println(this.getName() + " cracked the vault! Password: " + mid);
+                System.out.println("Binary search completed in " + attempts + " attempts");
+                System.exit(0);
+            } else if (result == -1) {
+                // less than password
+                low = mid + 1;
+            } else {
+                // bigger than Password
+                high = mid - 1;
+            }
+        }
+    }
+}
\ No newline at end of file

src/Main.java

@@ -6,12 +6,14 @@ public class Main {
 
         AscendingHackerThread ascendingHacker = new AscendingHackerThread(vault);
         DescendingHackerThread descendingHacker = new DescendingHackerThread(vault);
+        BinarySearchHackerThread binarySearchHacker = new BinarySearchHackerThread(vault);
         PoliceThread police = new PoliceThread();
 
         System.out.println("Starting all threads...");
 
         ascendingHacker.start();
         descendingHacker.start();
+        binarySearchHacker.start();
         police.start();
 
         System.out.println("All threads are running !");

src/Vault.java

@@ -13,4 +13,21 @@ public class Vault {
         }
         return guess == this.password;
     }
+
+    public int comparePassword(int guess) {
+        try {
+            Thread.sleep(5);
+        } catch (InterruptedException e) {
+            System.out.println("Exception during password comparison");
+        }
+
+        if (guess == this.password) {
+            return 0;
+        } else if (guess < this.password) {
+            return -1;
+        } else {
+            return 1;
+        }
+    }
+
 }
\ No newline at end of file