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Farm Trail 农场小路

Farm Trail曾出现于第23届WPC Round 2 第7题。

规则

Farm Trail,23rd WPC Instrucion Booklet © 2014, UK Puzzle Association
Farm Trail,23rd WPC Instrucion Booklet © 2014, UK Puzzle Association
规则
这表格代表分成数个区块的农场。某些格子豢养了动物, 而这些格子彼此不得以边相接。题目已提供了数字, 代表在每个区块中有多少格有动物。请推导出动物所在位置, 并且从表格左上角的旗帜开始, 画一条环状的路径回到原点。这条路径必须经过表格中除了树及动物以外的每个格子。而路径本身只能直向或横向连接, 且不能碰到或跨越自己。另外, 当路径离开了第一个区块后, 在回到第一区块之前。它到每个区域只能经过一次(译注: 也就是除了第一区块外, 不能去了别的区域后又回来原来的区域)。
Rule
The grid represents a farm which is divided into fields. Certain cells are occupied by an animal and these cells cannot touch orthogonally. The number of animals in each field is given. Deduce the positions of the animals and draw a trail which starts and ends at the flag in the top left corner of the grid and visits every cell except for those occupied by a tree or an animal. The trail moves orthogonally between the centre of cells and does not touch or cross itself. Once the trail leaves the first field, it enters the remaining fields exactly once each before returning to the first field again.
Farm Trail答案,23rd WPC Instrucion Booklet © 2014, UK Puzzle Association
Farm Trail答案,23rd WPC Instrucion Booklet © 2014, UK Puzzle Association

解题技巧

  • 因为每一区都只能经过一次, 代表只要一走进去就要走完全部的格子才能再走到下一区, 进去和出来各只有一次的机会, 所以从第一区走出及回来不能是去同一区, 同理别区也是, 如此就可以比较快判断出来路线大致的走法。
  • 再来动物的位置因为不能相邻, 所以只要标示出来, 它的上下左右四格就标上点代表是路线。最后有些区域比较狭长, 此时中间的格子就一定不能是动物, 因为它会造成两端的路线断开(但路线要一次走完)。

参考资料