Update problem-sets-competitive-programming.md (#4346)

* Update problem-sets-competitive-programming.md

* Update problem-sets-competitive-programming.md

* Update problem-sets-competitive-programming.md

* alphabetize, remove commentary

Co-authored-by: Eric Hellman <eric@hellman.net>

problem-sets-competitive-programming.md

@@ -57,8 +57,10 @@
 
 * [AIcrowd](https://www.aicrowd.com)
 * [CodaLab](https://competitions.codalab.org)
+* [CrowdANALYTIX](https://www.crowdanalytix.com/community)
 * [DrivenData](https://www.drivendata.org)
 * [Kaggle](https://www.kaggle.com)
+* [KDD Cup](https://www.kdd.org/kdd2019/kdd-cup)
 
 
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