First Bad Version : Accepted

Author: gouthampradhan

README.md

@@ -49,6 +49,7 @@ My accepted leetcode solutions to some of the common interview problems.
 - [Median of Two Sorted Arrays](problems/src/binary_search/MedianOfTwoSortedArrays.java) (Hard)
 - [Pow(x, n)](problems/src/binary_search/PowXN.java) (Medium)
 - [Find Peak Element](problems/src/binary_search/FindPeakElement.java) (Medium)
+- [First Bad Version](problems/src/binary_search/FirstBadVersion.java) (Easy)
 
 #### [Bit Manipulation](problems/src/bit_manipulation)
 

problems/src/binary_search/FirstBadVersion.java

@@ -0,0 +1,37 @@
+package binary_search;
+
+/**
+ * Created by gouthamvidyapradhan on 29/11/2017.
+ *
+ * You are a product manager and currently leading a team to develop a new product. Unfortunately, the latest version
+ * of your product fails the quality check. Since each version is developed based on the previous version,
+ * all the versions after a bad version are also bad.
+
+ Suppose you have n versions [1, 2, ..., n] and you want to find out the first bad one, which causes all the
+ following ones to be bad.
+
+ You are given an API bool isBadVersion(version) which will return whether version is bad. Implement a function to
+ find the first bad version. You should minimize the number of calls to the API.
+ */
+public class FirstBadVersion {
+    public static void main(String[] args) throws Exception{
+        System.out.println(new FirstBadVersion().firstBadVersion(2126753390));
+    }
+
+    public int firstBadVersion(int n) {
+        int low = 0, high = n;
+        while(low < high){
+            int mid = (low + high) >>> 1;
+            if(isBadVersion(mid)){
+                high = mid;
+            } else low = mid + 1;
+        }
+        return high;
+    }
+
+    private boolean isBadVersion(int n){
+        if(n >= 1702766719)
+            return true;
+        return false;
+    }
+}