高尔夫代码:激光 [英] Code Golf: Lasers

问题描述

按字符计数的最短代码，用于输入板的2D表示形式，并根据输入内容输出"true"或"false" .

The shortest code by character count to input a 2D representation of a board, and output 'true' or 'false' according to the input.

木板由4种类型的瓷砖制成:

The board is made out of 4 types of tiles:

 # - A solid wall
 x - The target the laser has to hit
 / or \ - Mirrors pointing to a direction (depends on laser direction)
 v, ^, > or < - The laser pointing to a direction (down, up, right and left respectively)

只有一台激光，只有一个目标.墙壁必须形成任何大小的实心矩形，并将激光和目标放置在内部. 房间"内的墙壁是可能的.

There is only one laser and only one target. Walls must form a solid rectangle of any size, where the laser and target are placed inside. Walls inside the 'room' are possible.

激光射线从其起点向其指向的方向射击.如果激光束撞击墙壁，它将停止.如果激光束击中镜子，它会向镜子指向的方向反弹90度.镜子是两面的，这意味着两面都是反射性的"，并且可能以两种方式反射光线.如果激光束撞击激光束(^v><)本身，则将其视为墙(激光束会破坏光束束，因此永远不会击中目标).

Laser ray shots and travels from its origin to the direction it's pointing. If a laser ray hits the wall, it stops. If a laser ray hits a mirror, it bounces 90 degrees to the direction the mirror points to. Mirrors are two sided, meaning both sides are 'reflective' and may bounce a ray in two ways. If a laser ray hits the laser (^v><) itself, it is treated as a wall (laser beam destroys the beamer and so it'll never hit the target).

Input:
    ##########
    #   / \  #
    #        #
    #   \   x#
    # >   /  #
    ########## 
Output:
    true

Input:
    ##########
    #   v x  #
    # /      #
    #       /#
    #   \    #
    ##########
Output:    
    false

Input:
    #############
    #     #     #
    # >   #     #
    #     #     #
    #     #   x #
    #     #     #
    #############
Output:
    false

Input:
    ##########
    #/\/\/\  #
    #\\//\\\ #
    #//\/\/\\#
    #\/\/\/x^#
    ##########
Output:
    true

代码计数包括输入/​​输出(即完整程序).

Code count includes input/output (i.e full program).

推荐答案

Perl， 166 160个字符

Perl， 251 248 246 222 214 208 203 201 193 190 180 176 173 170 166-> 160个字符.

Perl, 166 160 characters

Perl, 251 248 246 222 214 208 203 201 193 190 180 176 173 170 166 --> 160 chars.

当比赛结束时，解决方案的笔触为166，但是A. Rex找到了几种方法来减少另外6个字符:

Solution had 166 strokes when this contest ended, but A. Rex has found a couple ways to shave off 6 more characters:

s!.!$t{$s++}=$&!ge,$s=$r+=99for<>;%d='>.^1<2v3'=~/./g;($r)=grep$d|=$d{$t{$_}},%t;
{$_=$t{$r+=(1,-99,-1,99)[$d^=3*/\\/+m</>]};/[\/\\ ]/&&redo}die/x/?true:false,$/

第一行将输入加载到板子表%t中，其中$t{99*i+j}将字符保存在行 i ，列 j 处.然后，

The first line loads the input into %t, a table of the board where $t{99*i+j} holds the character at row i,column j. Then,

%d=split//,'>.^1<2v3' ; ($r)=grep{$d|=$d{$t{$_}}}%t

它在%t的元素中搜索与> ^ <或v相匹配的字符，并同时将$d设置为介于0和3之间的值，该值指示激光束的初始方向.

it searches the elements of %t for a character that matches > ^ < or v, and simultaneously sets $d to a value between 0 and 3 that indicates the initial direction of the laser beam.

在主循环中每次迭代的开始，如果光束当前在镜子上，我们将更新$d.对3进行XOR运算可以得到\镜像的正确行为，对3进行XOR运算可以得到/镜像的正确行为.

At the beginning of each iteration in the main loop, we update $d if the beam is currently on a mirror. XOR'ing by 3 gives the correct behavior for a \ mirror and XOR'ing by 1 gives the correct behavior for a / mirror.

$d^=3*/\\/+m</>

接下来，根据当前方向更新当前位置$r.

Next, the current position $r is updated accoring to the current direction.

$r+=(1,-99,-1,99)[$d] ; $_ = $t{$r}

我们将当前位置的字符分配给$_，以方便使用匹配运算符.

We assign the character at the current position to $_ to make convenient use of the match operators.

/[\/\\ ]/ && redo

如果我们在空格或镜像字符上，请继续.否则，如果我们位于目标($_ =~ /x/)上，则终止true，否则终止false.

Continue if we are on a blank space or a mirror character. Otherwise we terminate true if we are on the target ($_ =~ /x/) and false otherwise.

限制:可能无法解决超过99列的问题.可以删除此限制，但要多花3个字符，

Limitation: may not work on problems with more than 99 columns. This limitation could be removed at the expense of 3 more characters,

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