day 8

8/index.ts

@@ -0,0 +1,128 @@
+import { strictEqual } from 'assert';
+import { readFileToArray } from '../utils';
+
+class Screen {
+    w: number
+
+    h: number
+
+    pixels: string[][]
+
+    instructions: string[]
+
+    constructor(instructions: string[], w = 50, h = 6) {
+        this.instructions = instructions;
+        this.w = w;
+        this.h = h;
+
+        this.pixels = [];
+        for (let y = 0; y < this.h; y += 1) {
+            this.pixels[y] = (new Array(this.w)).fill('.');
+        }
+    }
+
+    private run() {
+        this.instructions.forEach((line) => {
+            const rectMatches = line.match(/^rect ([0-9]+)x([0-9]+)$/);
+            const rotateMatches = line.match(/^rotate (?:column|row) (x|y)=([0-9]+) by ([0-9]+)$/);
+
+            if (rectMatches) {
+                this.addRect(Number(rectMatches[1]), Number(rectMatches[2]));
+            } else if (rotateMatches) {
+                this.rotate(rotateMatches[1], Number(rotateMatches[2]), Number(rotateMatches[3]));
+            }
+        });
+    }
+
+    getPixelCount() {
+        this.run();
+
+        return this.pixels.reduce((acc, line) => acc + line.filter((char) => char === '#').length, 0);
+    }
+
+    printScreen() {
+        this.run();
+
+        this.pixels.forEach((line) => {
+            console.log(line.join(''));
+        });
+    }
+
+    private getY(index: number) {
+        let newIndex = index + 1;
+
+        if (newIndex < 1) {
+            newIndex += this.h;
+        } else if (index > this.h) {
+            newIndex -= this.h;
+        }
+
+        return newIndex - 1;
+    }
+
+    private getX(index: number) {
+        let newIndex = index + 1;
+
+        if (newIndex < 1) {
+            newIndex += this.w;
+        } else if (index > this.w) {
+            newIndex -= this.w;
+        }
+
+        return newIndex - 1;
+    }
+
+    private addRect(width: number, height: number) {
+        // console.log('addRect', width, height);
+
+        for (let y = 0; y < height; y += 1) {
+            for (let x = 0; x < width; x += 1) {
+                this.pixels[y][x] = '#';
+            }
+        }
+    }
+
+    private rotate(direction: string, index: number, by: number) {
+        for (let b = 0; b < by; b += 1) {
+            const clone: string[][] = JSON.parse(JSON.stringify(this.pixels));
+
+            if (direction === 'x') {
+                for (let y = 0; y < this.h; y += 1) {
+                    this.pixels[y][index] = clone[this.getY(y - 1)][index];
+                }
+            } else if (direction === 'y') {
+                for (let x = 0; x < this.w; x += 1) {
+                    this.pixels[index][x] = clone[index][this.getX(x - 1)];
+                }
+            }
+        }
+    }
+}
+
+function part1(data: string[]): number {
+    return (new Screen(data)).getPixelCount();
+}
+
+function part2(data: string[]) {
+    (new Screen(data)).printScreen();
+}
+
+try {
+    readFileToArray('./8/input.txt').then((data) => {
+        const testData = [
+            'rect 3x2',
+            'rotate column x=1 by 1',
+            'rotate row y=0 by 4',
+            'rotate column x=1 by 1',
+        ];
+
+        strictEqual((new Screen(testData, 7, 3)).getPixelCount(), 6);
+
+        console.log('Part 1', part1(data));
+
+        console.log('Part 2');
+        part2(data);
+    });
+} catch (err) {
+    console.log(err);
+}