advent-of-code

commit 7a4b8b331576881e4e16e21ba140f5894590bc89
parent 20c9963950516dc1108d5b81c37c2542ec490bc5
Author: finwo <finwo@pm.me>
Date:   Tue, 15 Nov 2022 16:37:34 +0100

Added 2015/03 solution

Diffstat:
A
2015/day-03/index.js
 | 
59
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 59 insertions(+), 0 deletions(-)
diff --git a/2015/day-03/index.js b/2015/day-03/index.js
@@ -0,0 +1,59 @@
+const fs = require('fs');
+const through = require('through2');
+
+let poss = (new Array(2)).fill(0).map(() => ({ x: 0, y: 0 }));
+let had  = [[1]];
+let cnt  = 1;
+
+fs.createReadStream('input')
+
+  // Convert to characters
+  .pipe(through(function(chunk, enc, cb) {
+    chunk = chunk.toString();
+    for(let i = 0; i < chunk.length; i++) {
+      this.push(chunk.charAt(i));
+    }
+    cb();
+  }))
+
+  // Walk through directions
+  .pipe(through(function(chunk, enc, cb) {
+    const c = chunk.toString();
+    let   m = true;
+
+    // Perform part 1 move
+    const pos = poss.shift();
+    switch(c) {
+      case '^': pos.y--; break;
+      case '<': pos.x--; break;
+      case '>': pos.x++; break;
+      case 'v': pos.y++; break;
+      default: m = false; break;
+    }
+
+    if (m) {
+      // Current mover has to wait for it's turn next round
+      poss.push(pos);
+    } else {
+      // Bail if no move was made
+      poss.unshift(pos);
+      return cb();
+    }
+
+    // Ensure the entry exists in our array & count houses with at least 1 present
+    if (!had[pos.x]) had[pos.x] = [];
+    if (!had[pos.x][pos.y]) {
+      had[pos.x][pos.y] = 0;
+      cnt++;
+    }
+
+    // Increase the counter on that house
+    had[pos.x][pos.y]++;
+
+    cb();
+  }))
+
+
+  .on('finish', () => {
+    console.log(`${poss.length} Santa` + (poss.length == 1 ? '' : 's') + ` visited ${cnt} houses`);
+  })