Day 25

Author: stevenhorsman

Diff for: day-25-four-dimensional-adventure/fourd.js

@@ -0,0 +1,99 @@
+class Point {
+  constructor(x, y, z, t) {
+    this.x = x;
+    this.y = y;
+    this.z = z;
+    this.t = t;
+  }
+
+  calculateManhattenDistance(point) {
+    return (
+      Math.abs(this.x - point.x) +
+      Math.abs(this.y - point.y) +
+      Math.abs(this.z - point.z) +
+      Math.abs(this.t - point.t)
+    );
+  }
+}
+
+class Constellation {
+  constructor(points) {
+    this.points = points;
+  }
+
+  addPoint(point) {
+    this.points.push(point);
+  }
+
+  addPoints(points) {
+    this.points = this.points.concat(points);
+  }
+
+  getPointDistance(point) {
+    let minDist = Number.MAX_SAFE_INTEGER;
+    this.points.forEach(member => {
+      const dist = point.calculateManhattenDistance(member);
+      if (dist < minDist) {
+        minDist = dist;
+      }
+    });
+    return minDist;
+  }
+
+  canMerge(constellation) {
+    //console.log('can merge', this, constellation);
+    return this.points.some(myPoint => {
+      return constellation.points.some(point => {
+        //console.log('distance', myPoint.calculateManhattenDistance(point));
+        return myPoint.calculateManhattenDistance(point) <= 3;
+      });
+    });
+  }
+}
+
+function consellationCount(input) {
+  let constellations = [];
+  let points = parseCoordinates(input);
+  points.forEach(point => {
+    //Add to first constellation that fits
+    const joined = constellations.some(constellation => {
+      if (constellation.getPointDistance(point) <= 3) {
+        constellation.addPoint(point);
+        return true;
+      }
+      return false;
+    });
+    if (!joined) {
+      constellations.push(new Constellation([point]));
+    }
+  });
+
+  //Now merge
+  let merge = false;
+  do {
+    merge = false;
+    constellations.forEach(constellationA => {
+      constellations.forEach(constellationB => {
+        if (
+          constellationA !== constellationB &&
+          constellationA.canMerge(constellationB)
+        ) {
+          merge = true;
+          constellationA.addPoints(constellationB.points);
+          const index = constellations.indexOf(constellationB);
+          constellations.splice(index, 1);
+        }
+      });
+    });
+  } while (merge);
+  return constellations.length;
+}
+
+function parseCoordinates(input) {
+  return input.split(/\r?\n/).map(line => {
+    line = line.trim();
+    return new Point(...line.split(','));
+  });
+}
+
+module.exports.consellationCount = consellationCount;