POJ 1753 Flip Game BFS+位压缩状态

最新推荐文章于 2023-12-02 22:53:12 发布

tao_tao_bu_jue

最新推荐文章于 2023-12-02 22:53:12 发布

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分类专栏： C++ POJ ACM 文章标签： each output integer search input up

本文链接：https://blog.youkuaiyun.com/tao_tao_bu_jue/article/details/2785561

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该博客介绍了一个使用BFS（广度优先搜索）和位压缩技术来解决POJ 1753翻转游戏的问题。通过读取输入，进行状态转移并利用哈希表避免重复状态，博主展示了如何找出达到特定目标状态所需的最小步数。代码中包括了状态结构、移动操作和搜索算法的实现。

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http://acm.pku.edu.cn/JudgeOnline/problem?id=1753

Flip Game

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 2565		Accepted: 1016

Description

Flip game is played on a rectangular 4x4 field with two-sided pieces placed on each of its 16 squares. One side of each piece is white and the other one is black and each piece is lying either it's black or white side up. Each round you flip 3 to 5 pieces, thus changing the color of their upper side from black to white and vice versa. The pieces to be flipped are chosen every round according to the following rules:

Choose any one of the 16 pieces.
Flip the chosen piece and also all adjacent pieces to the left, to the right, to the top, and to the bottom of the chosen piece (if there are any).

Consider the following position as an example:

bwbw
wwww
bbwb
bwwb
Here "b" denotes pieces lying their black side up and "w" denotes pieces lying their white side up. If we choose to flip the 1st piece from the 3rd row (this choice is shown at the picture), then the field will become:

bwbw
bwww
wwwb
wwwb
The goal of the game is to flip either all pieces white side up or all pieces black side up. You are to write a program that will search for the minimum number of rounds needed to achieve this goal.

Input

The input consists of 4 lines with 4 characters "w" or "b" each that denote game field position.

Output