1 files changed, 15 insertions, 0 deletions
diff --git a/2020/24/solve.js b/2020/24/solve.js
new file mode 100644
index 0000000..dca0e75
--- /dev/null
+++ b/2020/24/solve.js
@@ -0,0 +1,15 @@
+const { _, performance } = require("perf_hooks");
+const fs = require("fs");
+const I = fs.readFileSync("input", "utf8").split("\n");
+
+M={e:[0,1,-1],w:[0,-1,1],se:[1,0,-1],nw:[-1,0,1],ne:[-1,1,0],sw:[1,-1,0]};
+N=t=>Object.values(M).map(m=>t.split(",").map(Number).map((c,i)=>c+m[i])).map((n)=>n.join(","))
+B=(t,b)=>N(t).filter(n=>b.has(n))
+W=(t,b)=>N(t).filter(n=>!b.has(n))
+n=b=>{w=new Set([...b].flatMap(t=>W(t, b)));o=new Set();for(t of b){r=B(t,b);if(r.length>0&&r.length<=2)o.add(t)}for(t of w){r=B(t,b);if(r.length==2)o.add(t)}return o}
+s=_=>{D=I.map(t=>{D=[];for(i=0;i<t.length;i++){s=t.substring(i,i+2);if(t[i]=="e")D.push("e");else if(t[i]=="w")D.push("w");else if(s=="se"){D.push("se");i++}else if(s=="nw"){D.push("nw");i++}else if(s=="ne"){D.push("ne");i++}else if(s=="sw"){D.push("sw");i++}}return D});b=new Set();for(t of D){p=[0,0,0];for(d of t)for(i=0;i<3;i++)p[i]+=M[d][i];k=p.join(",");if(b.has(k))b.delete(k);else b.add(k)}console.log(b.size);for(i=0;i<100;i++)b=n(b);return b.size}
+
+const tic = performance.now();
+console.log(s());
+const toc = performance.now();
+console.log("TIME: " + ((toc - tic) / 1000).toFixed(6) + " seconds");