Update lab 12 skeleton

journal/_src/posts/2022-10-24-lab-12.md

@@ -1,5 +1,5 @@
     Title: Lab Twelve
-    Date: 2022-10-19T08:30:00
+    Date: 2022-10-24T08:30:00
     Tags: cs2613, lab, javascript
 
 Sample description

labs/L12/spec/village.spec.js

@@ -0,0 +1,28 @@
+let village = require("../village.js");
+let VillageState = village.VillageState;
+describe("roadGraph",
+	function () {
+		let roadGraph = village.roadGraph;
+		it("Alice's house",
+			() => expect(roadGraph["Alice's House"]).toEqual(["Bob's House", "Cabin", "Post Office"]));
+		it("Bob's house",
+			() => expect(roadGraph["Bob's House"]).toEqual(
+				jasmine.objectContaining(["Alice's House"])));
+	});
+
+
+describe("VillageState",
+	function () {
+		let first = new VillageState(
+			"Post Office",
+			[{ place: "Post Office", address: "Alice's House" }]
+		);
+		let next = first.move("Alice's House");
+		it("next place",
+			() => expect(next.place).toBe("Alice's House"));
+		it("next parcels",
+			() => expect(next.parcels).toEqual([]));
+		it("first place",
+			() => expect(first.place).toEqual("Post Office"));
+	}
+);

labs/L12/village.js

@@ -0,0 +1,48 @@
+const roads = [
+	"Alice's House-Bob's House", "Alice's House-Cabin",
+	"Alice's House-Post Office", "Bob's House-Town Hall",
+	"Daria's House-Ernie's House", "Daria's House-Town Hall",
+	"Ernie's House-Grete's House", "Grete's House-Farm",
+	"Grete's House-Shop", "Marketplace-Farm",
+	"Marketplace-Post Office", "Marketplace-Shop",
+	"Marketplace-Town Hall", "Shop-Town Hall"
+];
+function buildGraph(edges) {
+	let graph = Object.create(null);
+	function addEdge(from, to) {
+		if (graph[from] == null) {
+			graph[from] = [to];
+		} else {
+			graph[from].push(to);
+		}
+	}
+	for (let [from, to] of edges.map(r => r.split("-"))) {
+		addEdge(from, to);
+		addEdge(to, from);
+	}
+	return graph;
+}
+
+const roadGraph = buildGraph(roads);
+
+class VillageState {
+	constructor(place, parcels) {
+		this.place = place;
+		this.parcels = parcels;
+	}
+
+	move(destination) {
+		if (!roadGraph[this.place].includes(destination)) {
+			return this;
+		} else {
+			let parcels = this.parcels.map(p => {
+				if (p.place != this.place) return p;
+				return { place: destination, address: p.address };
+			}).filter(p => p.place != p.address);
+			return new VillageState(destination, parcels);
+		}
+	}
+}
+
+exports.roadGraph = roadGraph;
+exports.VillageState = VillageState;