摘要： B. Convex Shapetime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputConsider an n × m grid. Initially all the cells of the grid are colored white. Lenny has painted some of the cells (at least one) black. We call a painted grid convex if one can 阅读全文

摘要： A. Lights Outtime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputLenny is playing a game on a 3 × 3 grid of lights. In the beginning of the game all lights are switched on. Pressing any of the lights will toggle it and all side-adjacent lights. 阅读全文