IOM 2016, Блиц — Задача 41

Olympiad of Metropolises, Moscow. Blitz Contest, September, 5 · 5 септември 2016 г.

Условие

You are given a rectangle with sides of length 5 and 9. It is divided into square cells with sides of length 1. The bottom left corner cell has coordinates (0, 0), while the top right one has coordinates (4, 8).

You are located in the bottom left corner cell. You can move from any cell to the right or to the top to an adjacent cell.

The cells with coordinates (2, 0) and (1, 6) are impassable.

Find the number of ways to go to the top right corner cell.

Решение

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Оригинал в Архива: blitz.pdf