aoc 6+7+8+9

www/statics/aoc/2019/06_solution-2.ts

@@ -0,0 +1,102 @@
+namespace AdventOfCode2019_06_2
+{
+	const DAY     = 6;
+	const PROBLEM = 2;
+
+	class Body
+	{
+		name: string;
+		children: Body[] = [];
+		parent:   Body|null = null;
+
+		constructor(n: string) { this.name = n; }
+	}
+
+	class StellarSystem
+	{
+		com: Body;
+		bodies: { [key:string]:Body } = {};
+
+		constructor() { this.com = new Body("COM"); this.bodies["COM"] = this.com; }
+
+		private getOrCreate(name: string): Body 
+		{
+			if (name in this.bodies) return this.bodies[name];
+			return this.bodies[name] = new Body(name);
+		}
+
+		public add(mastername: string, slavename: string)
+		{
+			const master = this.getOrCreate(mastername);
+			const slave  = this.getOrCreate(slavename);
+
+			if (slave.parent !== null) throw "slave already has master";
+			slave.parent = master;
+
+			master.children.push(slave);
+		}
+
+		public getChecksum(): number
+		{
+			return this.calcChecksum(this.com, 0);
+		}
+
+		private calcChecksum(master: Body, depth: number): number
+		{
+			let r = depth;
+			for (const body of master.children)
+			{
+				r += this.calcChecksum(body, depth+1);
+			}
+			return r;
+		}
+
+		public getTransferDistance(ba: string, bb: string)
+		{
+			let dist: { [key:string]:number } = {};
+			
+			// From [BA] upwards
+			{
+				let obj = this.bodies[ba].parent;
+				let dctr = 0;
+				while(obj !== null)
+				{
+					dist[obj.name] = dctr;
+					dctr++;
+					obj = obj.parent;
+				}
+			}
+			
+			// From [BB] upwards
+			{
+				let obj = this.bodies[bb].parent;
+				let dctr = 0;
+				while(obj !== null)
+				{
+					if (obj.name in dist) return dctr + dist[obj.name];
+					dctr++;
+					obj = obj.parent;
+				}
+			}
+
+			return -1; // no path;
+		}
+	}
+
+	export async function run()
+	{
+		let input = await AdventOfCode.getInput(DAY);
+		if (input == null) return;
+
+		const data = input
+			.split(new RegExp('\r?\n'))
+			.filter(p => p.trim().length > 0)
+			.map(p => p.split(')'));
+
+		let sys = new StellarSystem();
+
+		for(const dat of data) sys.add(dat[0], dat[1]);
+
+		AdventOfCode.output(DAY, PROBLEM, sys.getTransferDistance("YOU", "SAN").toString());
+	}
+}