Can someone explain this question? (REDCGAME)

[ssjgz]

Looks like there’s a decent write-up here:

ACMIND18 - ICPC Online Round - Solution Outlines

Contest Link The problems can be solved in Practice section as well. ROBOGAME: The main observation was that if the ranges of any two robots had even a single cell in common, then they could coordinate their starting times so that they both collide. Hence, you just had to check if any of the ranges intersect or not. REDCGAME: At the end, there will only be one integer whose value is > K. The rest will all be exactly K , or if they had initially itself been < K, then they won’t change ever. …