add 275

Author: fishercoder1534

Diff for: README.md

@@ -276,6 +276,7 @@ Your ideas/fixes/algorithms are more than welcome!
 |278|[First Bad Version](https://leetcode.com/problems/first-bad-version/)|[Solution](../master/src/main/java/com/fishercoder/solutions/FirstBadVersion.java)| O(logn)|O(1) | Easy| Binary Search
 |277|[Find the Celebrity](https://leetcode.com/problems/find-the-celebrity/)|[Solution](../master/src/main/java/com/fishercoder/solutions/FindtheCelebrity.java)| O(n)|O(1) | Medium| 
 |276|[Paint Fence](https://leetcode.com/problems/paint-fence/)|[Solution](../master/src/main/java/com/fishercoder/solutions/PaintFence.java)| O(n)|O(1) | Easy| DP
+|275|[H-Index II](https://leetcode.com/problems/h-index-ii/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_275.java)| O(logn)|O(1) | Medium| Binary Search
 |274|[H-Index](https://leetcode.com/problems/h-index/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_274.java)| O(nlogn)|O(1) | Medium| 
 |273|[Integer to English Words](https://leetcode.com/problems/integer-to-english-words/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_273.java)| O(n)|O(1) | Hard| Math, String 
 |272|[Closest Binary Search Tree Value II](https://leetcode.com/problems/closest-binary-search-tree-value-ii/)|[Solution](../master/src/main/java/com/fishercoder/solutions/ClosestBinarySearchTreeValueII.java)| O(h+k)|O(h) | Hard| Stack

Diff for: src/main/java/com/fishercoder/solutions/_275.java

@@ -0,0 +1,24 @@
+package com.fishercoder.solutions;
+
+/**
+ * 275. H-Index II
+ * Follow up for H-Index: What if the citations array is sorted in ascending order? Could you optimize your algorithm?
+ */
+public class _275 {
+
+    public int hIndex(int[] citations) {
+        int left = 0;
+        int len = citations.length;
+        int right = len-1;
+        while (left <= right) {
+            int mid = left + (right-left)/2;
+            if (citations[mid] >= (len - mid)) {
+                right = mid - 1;
+            } else {
+                left = mid + 1;
+            }
+        }
+        return len - left;
+    }
+
+}