AoC day 4

AdventOfCode2018/4thDay/challenge2/challenge.txt

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+--- Part Two ---
+Strategy 2: Of all guards, which guard is most frequently asleep on the same minute?
+
+In the example above, Guard #99 spent minute 45 asleep more than any other guard or minute - three times in total. (In all other cases, any guard spent any minute asleep at most twice.)
+
+What is the ID of the guard you chose multiplied by the minute you chose? (In the above example, the answer would be 99 * 45 = 4455.)
+

AdventOfCode2018/4thDay/challenge2/index.js

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+class Guard {
+    constructor (id) {
+        this.id = id;
+        this.minutesAsleep = Array.from({ length: 60 }).map(() => 0);
+        this.fellAsleepAt = null;
+    }
+  
+    sleep (fellAsleepAt) {
+        this.fellAsleepAt = fellAsleepAt;
+    }
+  
+    awake (awokeAt) {
+        for (let i = this.fellAsleepAt; i < awokeAt; i++) {
+            this.minutesAsleep[i] += 1;
+        }
+    }
+  
+    get sleepiestMinute () {
+        return this.minutesAsleep
+            .map((value, index) => ({ index, value }))
+            .sort((a, b) => b.value - a.value)[0].index;
+        }
+  }
+  
+const sleep = (input) => {
+    const guards = {};
+    const schedule = input
+        .split('\n')
+        .map((x) => x.trim())
+        .sort()
+        .map((x) => {
+            const parts = x.match(/\[(\d{4})-(\d{2})-(\d{2}) (\d{2}):(\d{2})\] (.*)/);
+    
+            return {
+            minute: +parts[5],
+            message: parts[6],
+            };
+        });
+  
+    let currentGuard = null;
+  
+    for (let i = 0; i < schedule.length; i++) {
+        const { message, minute } = schedule[i];
+    
+        if (/Guard/.test(message)) {
+            const parts = message.match(/Guard #(\d+) begins shift/);
+            const guardId = +parts[1];
+            const guard = guards[guardId] ? guards[guardId] : new Guard(guardId);
+    
+            currentGuard = guards[guardId] = guard;
+        } else if (message === 'falls asleep') {
+            currentGuard.sleep(minute);
+        } else if (message === 'wakes up') {
+            currentGuard.awake(minute);
+        }
+    }
+  
+    const sleepiestGuard = Object
+        .keys(guards)
+        .map((guardId) => guards[guardId])
+        .sort((a, b) => b.minutesAsleep[b.sleepiestMinute] -
+                        a.minutesAsleep[a.sleepiestMinute])[0];
+  
+    return sleepiestGuard.id * sleepiestGuard.sleepiestMinute;
+};
+
+const fs = require('fs');
+console.log(sleep(fs.readFileSync("input.txt").toString()));