Create FirstBadVersion.java

Author: Foxeyyy

FirstBadVersion.java

@@ -0,0 +1,22 @@
+/* The isBadVersion API is defined in the parent class VersionControl.
+      boolean isBadVersion(int version); */
+
+public class Solution extends VersionControl {
+    public int firstBadVersion(int n) {
+        
+        int left = 1, right = n;
+        
+        while(left <= right) {
+            int mid = left + (right - left) / 2;
+            
+            if (!isBadVersion(mid)) {
+                left = mid + 1;
+            } else {
+                right = mid - 1;
+            }
+        }
+        
+        return left;
+        
+    }
+}