feat: Solution Day 25, ⭐ w/ TypeScript!

2021/deno/day-25.ts

@@ -0,0 +1,141 @@
+const input = await Deno.readTextFile("./input/day-25.in");
+// const input = await Deno.readTextFile("./input/example.in");
+
+function norm(x: number, y: number, width: number) {
+  return x + y * width;
+}
+
+function invNorm(normal: number, width: number) {
+  return { x: normal % width, y: Math.floor(normal / width) };
+}
+
+function calcAdj(index: number, width: number, height: number, type: string) {
+  const adj: number[] = [];
+  const { x, y } = invNorm(index, width);
+
+  if (type === "v") {
+    if (y + 1 < height) {
+      // down
+      adj.push(norm(x, y + 1, width));
+    }
+
+    if (y + 1 === height) {
+      // down wrap around
+      adj.push(norm(x, 0, width));
+    }
+  }
+
+  if (type === ">") {
+    if (x + 1 < width) {
+      // right
+      adj.push(norm(x + 1, y, width));
+    }
+
+    if (x + 1 === width) {
+      // right wrap around
+      adj.push(norm(0, y, width));
+    }
+  }
+
+  return adj;
+}
+
+function flatten2dMatrix<T>(matrix: T[][]): T[] {
+  const result: T[] = [];
+
+  for (let y = 0; y < matrix.length; y++) {
+    const row = matrix[y];
+    result.push(...row);
+  }
+
+  return result;
+}
+
+function unflatten2dMatrix<T>(
+  flatMatrix: T[],
+  width: number,
+  height: number
+): T[][] {
+  const result = [];
+
+  for (let y = 0; y < height; y++) {
+    const row = flatMatrix.slice(y * width, (y + 1) * width);
+    result.push(row);
+  }
+
+  return result;
+}
+
+function print(grid: string[], width: number, height: number) {
+  const m2d = unflatten2dMatrix(grid, width, height);
+
+  for (const row of m2d) {
+    console.log(row.join(""));
+  }
+}
+
+function hash(grid: string[], width: number, height: number) {
+  const m2d = unflatten2dMatrix(grid, width, height);
+
+  let result = "";
+
+  for (const row of m2d) {
+    result = `${result}:${row.join("")}`;
+  }
+
+  return result;
+}
+
+const grid = input.split("\n").map((row) => row.split(""));
+
+const height = grid.length;
+const width = grid[0].length;
+
+const map: string[] = flatten2dMatrix(grid);
+
+const turns = [">", "v"];
+
+let step = 0;
+
+while (1) {
+  const prev = hash(map, width, height);
+
+  for (const type of turns) {
+    let index = 0;
+
+    const update: { index: number; next: number; type: string }[] = [];
+
+    for (const item of map) {
+      if (item !== type) {
+        index += 1;
+        continue;
+      }
+
+      const [next] = calcAdj(index, width, height, item);
+
+      if (map[next] === ".") {
+        update.push({ index, next, type });
+      }
+
+      index += 1;
+    }
+
+    update.forEach(({ index, next, type }) => {
+      map[index] = ".";
+      map[next] = type;
+    });
+  }
+
+  step += 1;
+
+  const after = hash(map, width, height);
+
+  if (prev === after) break;
+
+  print(map, width, height);
+}
+
+/**
+ * Part One
+ */
+console.log("Part One:", step);