Codeforces Round 690 Div 3

Summary

... a4 a2 is this then the actual sequence that is going to be a1 a2 a3 a4 a5 all the way till a n would be here The sum so we basically sum up a i plus a i plus one plus a i plus two and then on plus equal into n choose ... but the key thing is that all the digits are distinct so firstly all the possible digits that we could have would be 0 1 2 And then so these two lists preserve the order so we know which l is linked to which are so it's one four two So we have i think you have optimized uh choosing now because now it's no longer and choose Replay of my post-contest stream after winning First place before systests! Hoping I don't fail anything, but I think my submissions are pretty safe. My screencast of live solving ...