Merge branch 'master' of github.com:haoel/leetcode

README.md

@@ -14,9 +14,10 @@ LeetCode
 |285|[Inorder Successor in BST](https://leetcode.com/problems/inorder-successor-in-bst/) ♥ | [Java](./algorithms/java/src/inorderSuccessorInBST/inorderSuccessorInBST.java)|Medium|
 |283|[Move Zeroes](https://leetcode.com/problems/move-zeroes/)  | [C++](./algorithms/cpp/moveZeroes/moveZeroes.cpp)|Easy|
 |278|[First Bad Version](https://leetcode.com/problems/first-bad-version/)| [C++](./algorithms/cpp/firstBadVersion/FirstBadVersion.cpp), [Java](./algorithms/java/src/firstBadVersion/firstBadVersion.java)|Easy|
+|274|[H-Index](https://leetcode.com/problems/h-index/)| [C++](./algorithms/cpp/h-Index/h-Index.cpp)|Medium|
 |273|[Integer to English Words](https://leetcode.com/problems/integer-to-english-words/)| [C++](./algorithms/cpp/integerToEnglishWords/IntegerToEnglishWords.cpp)|Medium|
 |268|[Missing Number](https://leetcode.com/problems/missing-number/)| [C++](./algorithms/cpp/missingNumber/MissingNumber.cpp)|Medium|
-|264|[Ugly Number II](https://leetcode.com/problems/ugly-number/)| [C++](./algorithms/cpp/uglyNumber/UglyNumber.II.cpp)|Medium|
+|264|[Ugly Number II](https://leetcode.com/problems/ugly-number-ii/)| [C++](./algorithms/cpp/uglyNumber/UglyNumber.II.cpp)|Medium|
 |263|[Ugly Number](https://leetcode.com/problems/ugly-number/)| [C++](./algorithms/cpp/uglyNumber/UglyNumber.cpp)|Easy|
 |258|[Add Digits](https://leetcode.com/problems/add-digits/)| [C++](./algorithms/cpp/addDigits/addDigits.cpp)|Easy|
 |226|[Valid Anagram](https://leetcode.com/problems/valid-anagram/)| [C++](./algorithms/cpp/anagrams/ValidAnagram.cpp)|Easy|

algorithms/cpp/h-Index/h-Index.cpp

@@ -0,0 +1,51 @@
+// Source : https://leetcode.com/problems/h_index/
+// Author : Calinescu Valentin
+// Date   : 2015-10-22
+
+/*************************************************************************************** 
+ *
+ * Given an array of citations (each citation is a non-negative integer) of a 
+ * researcher, write a function to compute the researcher's h-index.
+ * 
+ * According to the definition of h-index on Wikipedia: "A scientist has index h if h of
+ * his/her N papers have at least h citations each, and the other N − h papers have no
+ * more than h citations each."
+ * 
+ * For example, given citations = [3, 0, 6, 1, 5], which means the researcher has 5 
+ * papers in total and each of them had received 3, 0, 6, 1, 5 citations respectively.
+ * Since the researcher has 3 papers with at least 3 citations each and the remaining 
+ * two with no more than 3 citations each, his h-index is 3.
+ * 
+ * Note: If there are several possible values for h, the maximum one is taken as the 
+ * h-index.
+ *               
+ ***************************************************************************************/
+
+
+
+/* 
+ * Solutions
+ * =========
+ *
+ * A simple solution would be to sort the vector and then run through it starting with
+ * the last element. At every step we need to check whether this element is not less than
+ * the remaining number of elements bigger than it(including itself) and all the values of
+ * the other elements smaller than it are not more than that number. The h_index is this
+ * number of elements bigger than it(including itself).
+ * 
+ * Time Complexity: O(N log N)
+ * Space Complexity: O(1)
+ * 
+ */
+#include <algorithm>
+class Solution {
+public:
+    int hIndex(vector<int>& citations) {
+        sort(citations.begin(), citations.end());
+        int h_index = 0;
+        for(int i = citations.size() - 1; i >= 0; i--)
+            if(citations[i] >= citations.size() - i && (i - 1 < 0 || citations[i - 1] <= citations.size() - i))
+                h_index = citations.size() - i;
+        return h_index;
+    }
+};