2018 d4 p2 js

2018/4/part2.js

@@ -0,0 +1,46 @@
+const fs = require('fs');
+
+let input = fs.readFileSync('input.txt', 'utf-8').split('\n').sort((a, b) => val(a).getTime() - val(b).getTime());
+
+function val(a) {
+	let time = new Date(a.match(/\[(.*)\]/)[1]);
+	return time;
+}
+
+let guards = {};
+let id;
+let start;
+let shifts = []
+for (let line of input) {
+	let match = line.match(/#(\d+)/);
+	if (match) {
+		id = match[1];
+		if (!guards[id])
+			guards[id] = {};
+		shifts.push(id);
+	} else {
+		if (line.includes('falls')) {
+			start = val(line).getMinutes();
+		} else if (line.includes('wakes')) {
+			let end = val(line).getMinutes();
+			for (time = start; time < end; time++) {
+				guards[id][time] = (guards[id][time] || 0) + 1;
+			}
+		}
+	}
+}
+
+let theid;
+let themost = 0;
+let theminute;
+for (id in guards) {
+	let thismost = Object.entries(guards[id]).sort((a, b) => b[1] - a[1])[0];
+	if (!thismost) { continue }
+	if (thismost[1] > themost) {
+		theid = id;
+		themost = thismost[1];
+		theminute = Number(thismost[0])
+	}
+}
+
+console.log(`#${theid} * minute ${theminute} = ${theid * theminute}, ${themost} times`)

README.md

@@ -15,7 +15,7 @@ It's a fun challenge from [here](https://adventofcode.com).
 	* [1](https://adventofcode.com/2018/day/1) js * *
 	* [2](https://adventofcode.com/2018/day/2) py * *
 	* [3](https://adventofcode.com/2018/day/3) js * *
-	* [4](https://adventofcode.com/2018/day/4) js *
+	* [4](https://adventofcode.com/2018/day/4) js * *
 
 # Languages Used
 * Python