Add '2020/' from commit 'aaabfa90c9033044d0a9d5fe6776b718711ef46c'

git-subtree-dir: 2020
git-subtree-mainline: ab8f135946
git-subtree-split: aaabfa90c9

2020/05/part2.js

@@ -0,0 +1,36 @@
+const fs = require('fs');
+const readline = require('readline');
+const readInterface = readline.createInterface({input: fs.createReadStream('input'), console: false});
+
+let seats = []; // [[x,y], [x,y], ...]
+
+readInterface.on('line', function(line) {
+  let result = line.split('').reduce(function(sp, char) {
+    const halfX = Math.floor((1 + sp[2] - sp[0]) / 2);
+    const halfY = Math.floor((1 + sp[3] - sp[1]) / 2);
+
+    switch(char) {
+    case 'F': sp[3] -= halfY; break;
+    case 'B': sp[1] += halfY; break;
+    case 'L': sp[2] -= halfX; break;
+    case 'R': sp[0] += halfX; break;
+    };
+
+    return sp;
+  }, [0,0,7,127]);
+
+  seats.push([result[0], result[1]]);
+});
+
+readInterface.on('close', function(line) {
+  let seatIDs = new Set( seats.map((seat) => seat[1]*8 + seat[0]) );
+
+  for (x=0; x<8; x++) {
+    for(y=0; y<128; y++) {
+      let seatID = y*8+x;
+      if (!seatIDs.has(seatID) && seatIDs.has(seatID-1) && seatIDs.has(seatID+1)) {
+        console.log(seatID);
+      }
+    }
+  }
+});