day nine both parts

07/code.js

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+import { readFileSync } from 'node:fs';
+
+let sampleMode = false;
+let usedArray = [];
+
+const sampleArray = readFileSync('sample.txt').toString().split("\n");
+const inputArray = readFileSync('input.txt').toString().split("\n");
+
+if (sampleMode) {
+  usedArray = sampleArray;
+} else {
+  usedArray = inputArray;
+}
+
+// Part One
+
+console.time("part1");
+
+let newInput = JSON.parse(JSON.stringify(usedArray));
+for (let i = 0; i < newInput.length; i++) {
+  newInput[i] = newInput[i].split("");
+}
+
+for (let i = 1; i < newInput.length; i++) {
+  for (let j = 0; j < newInput[i].length; j++) {
+    if ((newInput[i - 1][j] === '|' || newInput[i - 1][j] === 'S') && newInput[i][j] === '.') {
+      newInput[i][j] = '|';
+    }
+    if (newInput[i - 1][j] === '|' && newInput[i][j] === '^') {
+      if (j > 0 && newInput[i][j - 1] === '.') {
+        newInput[i][j - 1] = '|';
+      }
+    }
+    if (newInput[i - 1][j] === '|' && newInput[i][j] === '^') {
+      if (j < newInput[i].length - 1 && newInput[i][j + 1] === '.') {
+        newInput[i][j + 1] = '|';
+      }
+    }
+  }
+}
+
+let splits = 0;
+
+for (let i = 1; i < newInput.length; i++) {
+  for (let j = 0; j < newInput[i].length; j++) {
+    if (newInput[i][j] === '^' && newInput[i - 1][j] === '|') {
+      splits++;
+    }
+  }
+}
+
+console.timeEnd("part1");
+console.log(splits);
+
+
+// Part Two
+
+console.time("part2");
+
+newInput = JSON.parse(JSON.stringify(usedArray));
+for (let i = 0; i < newInput.length; i++) {
+  newInput[i] = newInput[i].split("");
+}
+
+for (let i = 1; i < newInput.length; i++) {
+  for (let j = 0; j < newInput[i].length; j++) {
+    if (newInput[i - 1][j] === 'S') {
+      newInput[i][j] = 1;
+    }
+    if (Number.parseInt(newInput[i - 1][j]) > 0 && Number.parseInt(newInput[i][j]) > 0) {
+      newInput[i][j] = newInput[i][j] + newInput[i - 1][j];
+    }
+    if ((Number.parseInt(newInput[i - 1][j]) > 0) && newInput[i][j] === '.') {
+      newInput[i][j] = newInput[i - 1][j];
+    }
+    if (Number.parseInt(newInput[i - 1][j]) > 0 && newInput[i][j] === '^') {
+      if (j > 0 && newInput[i][j - 1] === '.') {
+        newInput[i][j - 1] = newInput[i - 1][j];
+      } else if (j > 0 && Number.parseInt(newInput[i][j - 1]) > 0) {
+        newInput[i][j - 1] = Number.parseInt(newInput[i][j - 1]) + newInput[i - 1][j];
+      }
+      if (j < newInput[i].length - 1 && newInput[i][j + 1] === '.') {
+        newInput[i][j + 1] = newInput[i - 1][j];
+      } else if (j < newInput[i].length - 1 && Number.parseInt(newInput[i][j + 1]) > 0) {
+        newInput[i][j + 1] = Number.parseInt(newInput[i][j + 1]) + newInput[i - 1][j];
+      }
+    }
+  }
+}
+
+let timelines = 0;
+
+const bottomRow = newInput[newInput.length - 1];
+for (let i = 0; i < bottomRow.length; i++) {
+  if (Number.parseInt(bottomRow[i]) > 0) {
+    timelines += Number.parseInt(bottomRow[i]);
+  }
+}
+
+console.timeEnd("part2");
+console.log(timelines);
+
+// functions

08/code.js

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+import { readFileSync } from 'node:fs';
+
+let sampleMode = false;
+let usedArray = [];
+
+const sampleArray = readFileSync('sample.txt').toString().split("\n");
+const inputArray = readFileSync('input.txt').toString().split("\n");
+
+if (sampleMode) {
+  usedArray = sampleArray;
+} else {
+  usedArray = inputArray;
+}
+
+// Part One
+
+console.time("part1");
+
+let coordinatesArray = [];
+
+for (const element of usedArray) {
+  const coordinates = element.split(",");
+  coordinatesArray.push({ x: Number.parseInt(coordinates[0]), y: Number.parseInt(coordinates[1]), z: Number.parseInt(coordinates[2]) });
+}
+
+let segments = [];
+let parent = {};
+
+for (let i = 0; i < coordinatesArray.length; i++) {
+  for (let j = i + 1; j < coordinatesArray.length; j++) {
+    const x2 = Math.pow(coordinatesArray[i].x - coordinatesArray[j].x, 2);
+    const y2 = Math.pow(coordinatesArray[i].y - coordinatesArray[j].y, 2);
+    const z2 = Math.pow(coordinatesArray[i].z - coordinatesArray[j].z, 2);
+    const distance = Math.sqrt(x2 + y2 + z2);
+    segments.push({ from: i, to: j, distance });
+  }
+}
+
+segments.sort((a, b) => a.distance - b.distance);
+const shortest = segments.slice(0, sampleMode ? 10 : 1000);
+
+for (const seg of shortest) {
+  union(seg.from, seg.to);
+}
+
+const circuits = {};
+for (const seg of shortest) {
+  const root = find(seg.from);
+  circuits[root] = circuits[root] || new Set();
+  circuits[root].add(seg.from);
+  circuits[root].add(seg.to);
+}
+
+const circuitList = Object.values(circuits);
+const sizes = circuitList.map(nodes => nodes.size).sort((a, b) => b - a);
+const result = sizes[0] * sizes[1] * sizes[2];
+
+console.timeEnd("part1");
+console.log(result);
+
+// Part Two
+
+console.time("part2");
+
+coordinatesArray = [];
+
+for (const element of usedArray) {
+  const coordinates = element.split(",");
+  coordinatesArray.push({ x: Number.parseInt(coordinates[0]), y: Number.parseInt(coordinates[1]), z: Number.parseInt(coordinates[2]) });
+}
+
+segments = [];
+parent = {};
+
+for (let i = 0; i < coordinatesArray.length; i++) {
+  for (let j = i + 1; j < coordinatesArray.length; j++) {
+    const x2 = Math.pow(coordinatesArray[i].x - coordinatesArray[j].x, 2);
+    const y2 = Math.pow(coordinatesArray[i].y - coordinatesArray[j].y, 2);
+    const z2 = Math.pow(coordinatesArray[i].z - coordinatesArray[j].z, 2);
+    const distance = Math.sqrt(x2 + y2 + z2);
+    segments.push({ from: i, to: j, distance });
+  }
+}
+
+segments.sort((a, b) => a.distance - b.distance);
+let circuitCount = coordinatesArray.length;
+let lastSegment;
+for (const seg of segments) {
+  const rootFrom = find(seg.from);
+  const rootTo = find(seg.to);
+
+  if (rootFrom !== rootTo) {
+    union(seg.from, seg.to);
+    circuitCount--;
+    lastSegment = seg;
+
+    if (circuitCount === 1) break;
+  }
+}
+
+const result2 = coordinatesArray[lastSegment.from].x * coordinatesArray[lastSegment.to].x;
+
+console.timeEnd("part2");
+console.log(result2);
+
+// functions
+
+function find(x) {
+  if (parent[x] === undefined) parent[x] = x;
+  if (parent[x] !== x) parent[x] = find(parent[x]);
+  return parent[x];
+}
+
+function union(a, b) {
+  const rootA = find(a);
+  const rootB = find(b);
+  if (rootA !== rootB) {
+    parent[rootA] = rootB;
+  }
+}

09/code.js

@@ -0,0 +1,151 @@
+import { readFileSync } from 'node:fs';
+
+let sampleMode = false;
+let usedArray = [];
+
+const sampleArray = readFileSync('sample.txt').toString().split("\n");
+const inputArray = readFileSync('input.txt').toString().split("\n");
+
+if (sampleMode) {
+  usedArray = sampleArray;
+} else {
+  usedArray = inputArray;
+}
+
+// Part One
+
+console.time("part1");
+
+let coordinatesArray = [];
+
+for (const element of usedArray) {
+  const coordinates = element.split(",");
+  coordinatesArray.push({ x: Number.parseInt(coordinates[0]), y: Number.parseInt(coordinates[1]) });
+}
+
+let segments = [];
+
+for (let i = 0; i < coordinatesArray.length; i++) {
+  for (let j = i + 1; j < coordinatesArray.length; j++) {
+    const dx = Math.abs(coordinatesArray[i].x - coordinatesArray[j].x) + 1;
+    const dy = Math.abs(coordinatesArray[i].y - coordinatesArray[j].y) + 1;
+    const area = dx * dy;
+    segments.push({ dx: dx, dy: dy, area: area });
+  }
+}
+
+segments.sort((a, b) => a.area > b.area ? -1 : 1);
+
+console.timeEnd("part1");
+console.log(segments[0].area);
+
+
+// Part Two
+
+console.time("part2");
+
+// Only collect the RED tile coordinates (endpoints)
+const xSet = new Set();
+const ySet = new Set();
+
+for (const tile of coordinatesArray) {
+  xSet.add(tile.x);
+  ySet.add(tile.y);
+}
+
+const xCoords = [...xSet].sort((a, b) => a - b);
+const yCoords = [...ySet].sort((a, b) => a - b);
+
+// Store horizontal and vertical line segments for boundary checking
+const hLines = []; // {y, x1, x2}
+const vLines = []; // {x, y1, y2}
+
+for (let i = 0; i < coordinatesArray.length; i++) {
+  const curr = coordinatesArray[i];
+  const next = coordinatesArray[(i + 1) % coordinatesArray.length];
+
+  if (curr.x === next.x) {
+    vLines.push({ x: curr.x, y1: Math.min(curr.y, next.y), y2: Math.max(curr.y, next.y) });
+  } else {
+    hLines.push({ y: curr.y, x1: Math.min(curr.x, next.x), x2: Math.max(curr.x, next.x) });
+  }
+}
+
+// Check if a point is on the boundary
+function isOnBoundary(x, y) {
+  for (const line of hLines) {
+    if (y === line.y && x >= line.x1 && x <= line.x2) return true;
+  }
+  for (const line of vLines) {
+    if (x === line.x && y >= line.y1 && y <= line.y2) return true;
+  }
+  return false;
+}
+
+// Check if a point is inside using ray casting (count vertical line crossings to the left)
+function isInside(x, y) {
+  let crossings = 0;
+  for (const line of vLines) {
+    if (line.x < x && y >= line.y1 && y < line.y2) {
+      crossings++;
+    }
+  }
+  return crossings % 2 === 1;
+}
+
+// Check if a point is valid (on boundary or inside)
+function isValid(x, y) {
+  return isOnBoundary(x, y) || isInside(x, y);
+}
+
+// Check if entire rectangle is valid
+function isRectValid(x1, y1, x2, y2) {
+  // Check all corner and edge points at compressed coordinates within the rectangle
+  for (const y of yCoords) {
+    if (y < y1 || y > y2) continue;
+    for (const x of xCoords) {
+      if (x < x1 || x > x2) continue;
+      if (!isValid(x, y)) return false;
+    }
+  }
+
+  // Also check if any boundary line crosses through the rectangle's interior
+  // creating an "outside" region
+  for (const line of vLines) {
+    if (line.x > x1 && line.x < x2) {
+      // Vertical line inside rectangle - check if it creates a gap
+      if (line.y1 > y1 || line.y2 < y2) {
+        // Line doesn't span full height - might create invalid region
+        if (line.y1 > y1 && !isValid(line.x, y1)) return false;
+        if (line.y2 < y2 && !isValid(line.x, y2)) return false;
+      }
+    }
+  }
+
+  return true;
+}
+
+// Find largest valid rectangle with red corners
+let maxArea = 0;
+
+for (let i = 0; i < coordinatesArray.length; i++) {
+  for (let j = i + 1; j < coordinatesArray.length; j++) {
+    const r1 = coordinatesArray[i];
+    const r2 = coordinatesArray[j];
+
+    const x1 = Math.min(r1.x, r2.x);
+    const x2 = Math.max(r1.x, r2.x);
+    const y1 = Math.min(r1.y, r2.y);
+    const y2 = Math.max(r1.y, r2.y);
+
+    if (isRectValid(x1, y1, x2, y2)) {
+      const area = (x2 - x1 + 1) * (y2 - y1 + 1);
+      if (area > maxArea) maxArea = area;
+    }
+  }
+}
+
+console.timeEnd("part2");
+console.log(maxArea);
+
+// functions