Add solution #275

Author: JoshCrozier

README.md

@@ -219,6 +219,7 @@
 268|[Missing Number](./0268-missing-number.js)|Easy|
 273|[Integer to English Words](./0273-integer-to-english-words.js)|Hard|
 274|[H-Index](./0274-h-index.js)|Medium|
+275|[H-Index II](./0275-h-index-ii.js)|Medium|
 278|[First Bad Version](./0278-first-bad-version.js)|Medium|
 282|[Expression Add Operators](./0282-expression-add-operators.js)|Hard|
 283|[Move Zeroes](./0283-move-zeroes.js)|Easy|

solutions/0275-h-index-ii.js

@@ -0,0 +1,34 @@
+/**
+ * 275. H-Index II
+ * https://leetcode.com/problems/h-index-ii/
+ * Difficulty: Medium
+ *
+ * Given an array of integers citations where citations[i] is the number of citations a
+ * researcher received for their ith paper and citations is sorted in ascending order,
+ * return the researcher's h-index.
+ *
+ * According to the definition of h-index on Wikipedia: The h-index is defined as the
+ * maximum value of h such that the given researcher has published at least h papers
+ * that have each been cited at least h times.
+ *
+ * You must write an algorithm that runs in logarithmic time.
+ */
+
+/**
+ * @param {number[]} citations
+ * @return {number}
+ */
+var hIndex = function(citations) {
+  let start = 0;
+
+  for (let end = citations.length - 1; start <= end;) {
+    const middle = Math.floor((start + end) / 2);
+    if (citations.length - middle - 1 < citations[middle]) {
+      end = middle - 1;
+    } else {
+      start = middle + 1;
+    }
+  }
+
+  return citations.length - start;
+};