시간 제한 | 메모리 제한 | 제출 | 정답 | 맞힌 사람 | 정답 비율 |
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1 초 | 128 MB | 398 | 110 | 80 | 22.989% |
This past fall, Farmer John took the cows to visit a corn maze. But this wasn't just any corn maze: it featured several gravity-powered teleporter slides, which cause cows to teleport instantly from one point in the maze to another. The slides work in both directions: a cow can slide from the slide's start to the end instantly, or from the end to the start. If a cow steps on a space that hosts either end of a slide, she must use the slide.
The outside of the corn maze is entirely corn except for a single exit.
The maze can be represented by an N x M (2 ≤ N ≤ 300; 2 ≤ M ≤ 300) grid. Each grid element contains one of these items:
A cow can only move from one space to the next if they are adjacent and neither contains corn. Each grassy space has four potential neighbors to which a cow can travel. It takes 1 unit of time to move from a grassy space to an adjacent space; it takes 0 units of time to move from one slide endpoint to the other.
Corn-filled spaces are denoted with an octothorpe (#). Grassy spaces are denoted with a period (.). Pairs of slide endpoints are denoted with the same uppercase letter (A-Z), and no two different slides have endpoints denoted with the same letter. The exit is denoted with the equals sign (=).
Bessie got lost. She knows where she is on the grid, and marked her current grassy space with the 'at' symbol (@). What is the minimum time she needs to move to the exit space?
Consider the following grid, with N=5 and M=6:
###=## #.W.## #.#### #.@W## ######
A single slide has endpoints denoted by an uppercase W. Her optimal strategy is to move right to the slide endpoint in 1 time, take the slide in 0 time to the other endpoint, and move right and up in 2 more time to end on the exit. This requires a total of 3 time, the minimum.
5 6 ###=## #.W.## #.#### #.@W## ######
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