Today I screencast and explained solutions of problems A–D and F. The video is uploaded to YouTube: https://youtu.be/B48ykX0NpUY↵
↵
I have to inform that the round quality wasn't exceptionally high: the translation was noticeably Google translated from Russian (for example, представление has at least two meanings — representation or performance, and Google Translate wasn't able to discriminate between these two), the pretests were weak in B, C and F (many people were simply TL-hacked or had their solution fail during system testing). I will elaborate on problem F: there I wrote a square root decomposition with incorrect constants, but still got AC though my solution was incorrect on these simple tests:↵
↵
```↵
2 3↵
2 2↵
```↵
↵
and↵
↵
```↵
4 24↵
5 5 5 5↵
```↵
↵
With the first of these, I was able to uphack six accepted solutions, including my own.↵
↵
Nevertheless I knew what to expect (I call such rounds _contests for schoolchildren_) and overall experience was satisfactory.
↵
I have to inform that the round quality wasn't exceptionally high: the translation was noticeably Google translated from Russian (for example, представление has at least two meanings — representation or performance, and Google Translate wasn't able to discriminate between these two), the pretests were weak in B, C and F (many people were simply TL-hacked or had their solution fail during system testing). I will elaborate on problem F: there I wrote a square root decomposition with incorrect constants, but still got AC though my solution was incorrect on these simple tests:↵
↵
```↵
2 3↵
2 2↵
```↵
↵
and↵
↵
```↵
4 24↵
5 5 5 5↵
```↵
↵
With the first of these, I was able to uphack six accepted solutions, including my own.↵
↵
Nevertheless I knew what to expect (I call such rounds _contests for schoolchildren_) and overall experience was satisfactory.
