2022/9 fix p2

Author: Joxter

day-09_p2_wrong/input.txt day-09/input.txtday-09_p2_wrong/input.txt renamed to day-09/input.txt

@@ -0,0 +1,127 @@
+import fs from 'fs';
+
+// https://adventofcode.com/2022/day/9
+
+let testInput = fs.readFileSync('./testData.txt').toString();
+let inputData = fs.readFileSync('./input.txt').toString();
+
+console.log('test_actual OK: ', part1_correct(testInput, 1) === 13);
+console.log('answer_actual: ', part1_correct(inputData, 1), [6018]);
+
+let test2Input = `R 5
+U 8
+L 8
+D 3
+R 17
+D 10
+L 25
+U 20`;
+console.log('test2 OK: ', part2(test2Input) === 36);
+console.log('answer2: ', part2(inputData), [2619]); // 491 is wrong???? correct 2619 O_o
+
+function part1_correct(inp) {
+  return correct_approach_actually(inp, 1);
+}
+
+function part2(inp) {
+  return correct_approach_actually(inp, 9);
+}
+
+function correct_approach_actually(inp, ropeLen) {
+  let history = new Set();
+  let rope = Array.from({ length: ropeLen + 1 }, () => {
+    return [0, 0];
+  });
+  let delta = { 'U': [1, 0], 'D': [-1, 0], 'R': [0, 1], 'L': [0, -1], };
+
+  // fs.writeFileSync('./out.txt', '');
+
+  inp.split('\n').map((line) => {
+    let [direction, steps] = line.split(' ');
+    steps = +steps;
+    // fs.appendFileSync('./out.txt', `${line}\n`);
+
+    while (steps--) {
+      rope[0][0] += delta[direction][0];
+      rope[0][1] += delta[direction][1];
+
+      for (let i = 1; i < rope.length; i++) {
+        rope[i] = follow(rope[i], rope[i - 1]);
+        // renderHistory(50, 50, [15, 21], history, rope);
+      }
+      history.add(rope[ropeLen].join(','));
+    }
+    // renderHistory(50, 50, [15, 21], history, rope);
+  });
+  // renderHistory(13, 30, [5, 11], history, rope);
+
+  return history.size;
+}
+
+function lengthBetween(a, b) {
+  return Math.max(Math.abs(a[0] - b[0]), Math.abs(a[1] - b[1]));
+}
+
+function follow(tail, head) {
+  let res = [...tail];
+  if (lengthBetween(tail, head) < 2) return res;
+
+  if (tail[0] === head[0]) {
+    if (tail[1] < head[1]) res[1]++;
+    if (tail[1] > head[1]) res[1]--;
+    return res;
+  }
+
+  if (tail[1] === head[1]) {
+    if (tail[0] < head[0]) res[0]++;
+    if (tail[0] > head[0]) res[0]--;
+    return res;
+  }
+
+  if (tail[0] < head[0]) {
+    res[0]++;
+  } else {
+    res[0]--;
+  }
+
+  if (tail[1] < head[1]) {
+    res[1]++;
+  } else {
+    res[1]--;
+  }
+  return res;
+}
+
+function renderHistory(height, width, focus, history, rope) {
+  let field = Array.from({ length: height }, () => {
+    return Array.from({ length: width }, () => {
+      return '.';
+    });
+  });
+
+  history.forEach((cell) => {
+    const [x, y] = cell.split(',').map(it => +it);
+
+    if (field[x + focus[0]] && field[x + focus[0]][y + focus[1]]) {
+      field[x + focus[0]][y + focus[1]] = '#';
+    }
+  });
+
+  rope.forEach(([x, y], i) => {
+    // const [x, y] = cell.split(',').map(it => +it);
+
+    if (field[x + focus[0]] && field[x + focus[0]][y + focus[1]]) {
+      field[x + focus[0]][y + focus[1]] = i;
+    }
+  });
+
+  field.reverse();
+
+  let res = field.map((row) => {
+    return row.join('');
+  }).join('\n');
+  // console.log(res);
+
+  fs.appendFileSync('./out.txt', res);
+  fs.appendFileSync('./out.txt', '\n');
+}