# ICPC Regionals 2019 Practice Problem "Game of ORs" Not Available

**URL:** <https://discuss.codechef.com/t/icpc-regionals-2019-practice-problem-game-of-ors-not-available/86119>\
**Category:** help\
**Tags:** icpc\
**Created:** [February 27, 2021, 2:56am UTC](https://discuss.codechef.com/t/icpc-regionals-2019-practice-problem-game-of-ors-not-available/86119 "2021-02-27T02:56:03Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![r3novatio](https://discuss.codechef.com/user_avatar/discuss.codechef.com/r3novatio/32/52652_2.png) [@r3novatio](https://discuss.codechef.com/u/r3novatio)\
**Post date:** [February 27, 2021, 2:56am UTC](https://discuss.codechef.com/t/icpc-regionals-2019-practice-problem-game-of-ors-not-available/86119/1 "2021-02-27T02:56:03Z")

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I was trying the ICPC Asia Regionals 2019 ([link](https://www.codechef.com/ICPCIN19)). I found it quite odd that the 5th problem- “Game of ORs”, although visible, is not available for submission/practice. When I try to open it directly from practice ([link](https://www.codechef.com/problems/SUMOR)), it says “ATTENTION: Problem is not visible now. Please try again later.”

This feels like a bummer because I wanted to test out my solution but couldn’t find this problem anywhere on the internet apart from here on codechef and over here, out of all 8 problems, only this one is not available for submission for some weird reason.

I request the codechef admins to look into this, and I ask if anyone else knows where I can find an OJ for the problem (I tried [https://icpcarchive.ecs.baylor.edu/](https://icpcarchive.ecs.baylor.edu/) but it only has up to 2017 regionals unfortunately)

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**Author:** ![explodingfrz](https://discuss.codechef.com/user_avatar/discuss.codechef.com/explodingfrz/32/208155_2.png) [@explodingfrz](https://discuss.codechef.com/u/explodingfrz)\
**Post date:** [February 27, 2021, 3:29am UTC](https://discuss.codechef.com/t/icpc-regionals-2019-practice-problem-game-of-ors-not-available/86119/2 "2021-02-27T03:29:49Z")

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The problem’s intended solution was wrong and it was later shown that the problem is NP Hard so no answer exists for the constraints.

Edit: I can’t find the post with the proof for its NP Hard nature but I’m pretty someone reduced the [bin packing problem](https://en.wikipedia.org/wiki/Bin_packing_problem) to SUMOR, thereby showing it was NP hard.