Day 10

10/input

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+noop
+addx 5
+noop
+addx 3
+addx -2
+addx 4
+noop
+noop
+noop
+noop
+noop
+addx 7
+addx 3
+noop
+noop
+noop
+noop
+addx 5
+noop
+noop
+addx 5
+addx -10
+addx 2
+addx 14
+noop
+addx -38
+noop
+noop
+addx 5
+addx 2
+addx 2
+addx 3
+noop
+addx 20
+addx -19
+addx 28
+addx -21
+addx 2
+addx 3
+noop
+addx 2
+addx -4
+addx 5
+addx 2
+addx -4
+addx 11
+addx -27
+addx 28
+addx -38
+addx 5
+addx 2
+addx -1
+noop
+addx 6
+addx 3
+addx -2
+noop
+noop
+addx 7
+addx 2
+noop
+noop
+noop
+addx 5
+addx 3
+noop
+addx 2
+addx -11
+addx 6
+addx 8
+noop
+addx 3
+addx -37
+addx 1
+addx 5
+addx 2
+addx 3
+noop
+noop
+noop
+noop
+noop
+addx -5
+addx 13
+addx 2
+addx -8
+addx 9
+addx 4
+noop
+addx 5
+addx -2
+addx -14
+addx 21
+addx 1
+noop
+noop
+addx -38
+addx 2
+addx 5
+addx 2
+addx 3
+addx -2
+noop
+addx 11
+addx -6
+addx 5
+addx 2
+addx 3
+noop
+addx 2
+addx -10
+addx 15
+noop
+addx -24
+addx 17
+addx 10
+noop
+addx 3
+addx -38
+addx 5
+addx 2
+addx 3
+addx -2
+addx 2
+addx 7
+addx 1
+addx -1
+noop
+addx 5
+noop
+noop
+noop
+noop
+addx 3
+noop
+addx -21
+addx 28
+addx 1
+noop
+addx 2
+noop
+addx 3
+noop
+noop

10/solution.mjs

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+import { readFileSync } from 'node:fs';
+
+const input = readFileSync('input', 'utf-8');
+
+const cycles = input
+  .split('\n')
+  .filter(line => line)
+  .flatMap((() => {
+    let x = 1;
+    return (line) => {
+      if (line.startsWith('noop')) {
+        return [x];
+      }
+      if (line.startsWith('addx')) {
+        const add = parseInt(line.substring(5));
+        if (isNaN(add)) {
+          throw new Error('Invalid value for addx');
+        }
+        const result = [x, x];
+        x += add;
+        return result;
+      }
+    };
+  })());
+
+const sumOfSignalStrengths = [20, 60, 100, 140, 180, 220]
+  .map(c => {
+    const x = cycles[c - 1];
+    const strength = c * x;
+    return strength;
+  })
+  .reduce((total, strength) => total + strength);
+
+console.log(
+  `The sum of observed signal strengths is: ${sumOfSignalStrengths}`
+);
+
+const render = cycles
+  .map((x, c) => {
+    const scanPos = c % 40;
+    return [x - 1, x, x + 1].some(pixelPos => pixelPos === scanPos);
+  })
+  .reduce((display, pixelVisible, c) => {
+    const scanLine = Math.floor(c / 40);
+    if (!display[scanLine]) {
+      display.push([]);
+    }
+    display[scanLine].push(pixelVisible ? '#' : ' ');
+    return display;
+  }, [])
+  .map(scanLine => scanLine.join(''))
+  .join('\n');
+
+console.log('Display output:');
+console.log(render);