ぷよぷよ19連鎖JavaScript版

JavaScript

ゲーム「ぷよぷよ」で、フィールドの状態がテキストで与えられたとき、消える「ぷよ」を消して次のフィールドの状態を出力するプログラムを書け。
http://okajima.air-nifty.com/b/2011/01/2011-ffac.html

前回書いたHaskell版のアルゴリズムのままJavaScriptに移植してみた。

const partition = (f,xs) => xs.reduce(([y,z],x) => f(x) ? [[...y,x],z] : [y,[...z,x]],[[],[]])
const cat = (x,[ok,ng]) => [[x,...ok.flat()],...ng]
const cmp = ([i,j,],[ii,jj,]) => i==ii ? j-jj : i-ii

const near = ([i,j,c],[ii,jj,cc]) => c==cc && (ii-i)**2+(jj-j)**2==1
const xyc = (n,xs) => xs.map((x,i) => [i/n|0,i%n,x])
const tr = xs => xs.map(([i,j,c]) => [j,i,c])
const str = xs => xs.sort(cmp).map(([,,c])=>c)

const joins = xs => xs.filter(([,,c])=>c.match(/\S/))
  .reduce((r,x)=>cat(x,partition(ys=>ys.some(y=>near(x,y)),r)),[])

const puyo = obj => {
  const xs = tr(xyc(obj.cols,obj.value.split("")))
  const j4 = joins(xs).filter(x=>x.length>3).flat()
  obj.value = str(tr(xyc(obj.rows,str(xs.map(x=>j4.some(y=>x+""==y+"") ? [x[0],-1," "] : x))))).join("")
}

<!DOCTYPE html>
<title>puyo</title>
<script src=puyo.js></script>
<form name=f>
<input type=button value=next onclick='puyo(document.f.t)'>
<input type=reset value=reset><br>
<textarea name=t rows=13 cols=7>
  GYRR
RYYGYG
GYGYRR
RYGYRG
YGYRYG
GYRYRG
YGYRYR
YGYRYR
YRRGRG
RYGYGG
GRYGYR
GRYGYR
GRYGYR
</textarea>
</form>