step6

src/hacker/BinarySearchHacker.java

+package hacker;
+
+public class BinarySearchHacker extends Thread {
+
+    private Vault vault;
+
+    public BinarySearchHacker(Vault vault) {
+        this.vault = vault;
+        this.setName("BinarySearchHacker");
+    }
+
+
+    public void run() {
+        int min = 0;
+        int max = 9999;
+
+        while (min <= max) {
+            // Calculate the middle guess
+            int y = (min + max) / 2;
+
+
+            //  verify
+            int result = vault.checkGuess(y);
+            if (result == 0) {
+                System.out.println(" The clever hacker succeeded " + this.getName() + " The password is: " + y);
+                System.exit(0);
+            } else if (result == -1) {
+                // The guess was too low ,Throw out the bottom half
+                min = y + 1;
+            } else { // result == 1
+                // The guess was too high, throw out the top half
+                max = y - 1;
+            }
+        }
+    }
+}
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