标签: 前缀和

「CodeForces 1247E」Rock Is Push

You are at the top left cell (1,1) of an 𝑛×𝑚 labyrinth. Your goal is to get to the bottom right cell (𝑛,𝑚). You can only move right or down, one cell per step. Moving right from a cell (𝑥,𝑦) takes you to the cell (𝑥,𝑦+1), while moving down takes you to the cell (𝑥+1,𝑦).