add 596

Author: fishercoder1534

README.md

@@ -43,6 +43,7 @@ Your ideas/fixes/algorithms are more than welcome!
 |600|[Non-negative Integers without Consecutive Ones](https://leetcode.com/problems/non-negative-integers-without-consecutive-ones/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_600.java) | O(log2(max_int) = 32) | O(log2(max_int) = 32) | Hard | Bit Manipulation, DP
 |599|[Minimum Index Sum of Two Lists](https://leetcode.com/problems/minimum-index-sum-of-two-lists/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_599.java) | O(max(m,n))|O(max(m,n)) | Easy | HashMap
 |598|[Range Addition II](https://leetcode.com/problems/range-addition-ii/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_598.java) | O(n) (n is the number of operations) |O(1) | Easy | 
+|596|[Classes More Than 5 Students](https://leetcode.com/problems/classes-more-than-5-students/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_596.java) | || Easy |
 |595|[Big Countries](https://leetcode.com/problems/big-countries/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_595.java) | O(n) |O(1) | Easy | 
 |594|[Longest Harmonious Subsequence](https://leetcode.com/problems/longest-harmonious-subsequence/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_594.java) | O(n) |O(n) | Easy | Array, HashMap
 |593|[Valid Square](https://leetcode.com/problems/valid-square/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_593.java) | O(1) |O(1) | Medium | Math

database/_596.sql

@@ -0,0 +1,3 @@
+select class from courses
+group by class
+having count(distinct student) >= 5;