Day 6

06/part1.js

@@ -0,0 +1,69 @@
+const { readFileSync } = require("fs");
+// Parse Input
+const inputFile = "input.txt";
+const input = readFileSync(inputFile).toString();
+const grid = [];
+input.split("\n").forEach((line) => grid.push(line.split("")));
+
+let playerPosition = [0, 0];
+let velocity = [0, -1];
+const visited = [];
+
+for (let y = 0; y < grid.length; y++) {
+  const line = grid[y];
+  for (let x = 0; x < line.length; x++) {
+    const element = line[x];
+    if (element == "^") {
+      playerPosition[0] = x;
+      playerPosition[1] = y;
+      grid[y][x] = ".";
+    }
+  }
+}
+
+function isInGrid(coord) {
+  let x = coord[0];
+  let y = coord[1];
+  return !(x < 0 || y < 0 || x >= grid[0].length || y >= grid.length);
+}
+
+function registerPosition(pos) {
+  let exist = visited.find((p) => p[0] == pos[0] && p[1] == pos[1]);
+  if (!exist) visited.push(pos);
+}
+
+function forward() {
+  registerPosition(playerPosition);
+
+  const nextPosition = [
+    playerPosition[0] + velocity[0],
+    playerPosition[1] + velocity[1],
+  ];
+
+  if (!isInGrid(nextPosition)) {
+    return true;
+  }
+
+  if (grid[nextPosition[1]][nextPosition[0]] == ".") {
+    playerPosition = nextPosition;
+  } else {
+    if (velocity[0] == 0 && velocity[1] == -1) {
+      velocity = [1, 0];
+    } else if (velocity[0] == 1 && velocity[1] == 0) {
+      velocity = [0, 1];
+    } else if (velocity[0] == 0 && velocity[1] == 1) {
+      velocity = [-1, 0];
+    } else if (velocity[0] == -1 && velocity[1] == 0) {
+      velocity = [0, -1];
+    }
+  }
+
+  return false;
+}
+
+let isFinished = forward();
+while (!isFinished) {
+  isFinished = forward();
+}
+
+console.log(visited.length);

06/part2.js

@@ -0,0 +1,84 @@
+const { readFileSync } = require("fs");
+// Parse Input
+const inputFile = "input.txt";
+const input = readFileSync(inputFile).toString();
+const grid = [];
+input.split("\n").forEach((line) => grid.push(line.split("")));
+
+let playerPosition = [0, 0];
+let velocity = [0, -1];
+
+for (let y = 0; y < grid.length; y++) {
+  const line = grid[y];
+  for (let x = 0; x < line.length; x++) {
+    const element = line[x];
+    if (element == "^") {
+      playerPosition[0] = x;
+      playerPosition[1] = y;
+      grid[y][x] = ".";
+    }
+  }
+}
+
+function isInGrid(coord) {
+  let x = coord[0];
+  let y = coord[1];
+  return !(x < 0 || y < 0 || x >= grid[0].length || y >= grid.length);
+}
+
+function forward() {
+  const nextPosition = [
+    playerPosition[0] + velocity[0],
+    playerPosition[1] + velocity[1],
+  ];
+
+  if (!isInGrid(nextPosition)) {
+    return true;
+  }
+
+  if (grid[nextPosition[1]][nextPosition[0]] == ".") {
+    playerPosition = nextPosition;
+  } else {
+    if (velocity[0] == 0 && velocity[1] == -1) {
+      velocity = [1, 0];
+    } else if (velocity[0] == 1 && velocity[1] == 0) {
+      velocity = [0, 1];
+    } else if (velocity[0] == 0 && velocity[1] == 1) {
+      velocity = [-1, 0];
+    } else if (velocity[0] == -1 && velocity[1] == 0) {
+      velocity = [0, -1];
+    }
+  }
+
+  return false;
+}
+
+let result = [];
+let initialPlayerPosition = playerPosition;
+for (let y = 0; y < grid.length; y++) {
+  const line = grid[y];
+  for (let x = 0; x < line.length; x++) {
+    process.stdout.write(
+      `y: ${y + 1}/${grid.length}; x: ${x + 1}/${grid[0].length}\r`,
+    );
+
+    if (
+      grid[y][x] == "." &&
+      !(x == initialPlayerPosition[0] && y == initialPlayerPosition[1])
+    ) {
+      playerPosition = initialPlayerPosition;
+      velocity = [0, -1];
+      grid[y][x] = "#";
+      let isFinished = false;
+      for (let i = 0; i < 1000000; i++) {
+        isFinished = forward();
+        if (isFinished) break;
+      }
+
+      if (!isFinished) result.push([x, y]);
+      grid[y][x] = ".";
+    }
+  }
+}
+
+console.log("\n", result.length);