2022-21 part 2 in js

1 files changed, 127 insertions, 0 deletions

diff --git a/2022/21-Monkey-Math/second.js b/2022/21-Monkey-Math/second.js
new file mode 100644
index 0000000..6932e13
--- /dev/null
+++ b/2022/21-Monkey-Math/second.js
@@ -0,0 +1,127 @@
+import * as fs from "fs";
+
+const simple = /(\w+): (\d+)/;
+const operation = /(\w+): (\w+) ([+\-*/]) (\w+)/;
+
+class Monkey {
+	constructor(line) {
+		// left and right are temporarily strings
+		this.left = null;
+		this.right = null;
+		this.up = null;
+		const s = line.match(simple);
+		if (s) {
+			this.name = s[1];
+			this.value = BigInt(s[2]);
+		} else {
+			const o = line.match(operation);
+			if (!o) throw "wtf";
+			this.name = o[1];
+			this.left = o[2];
+			this.operation = o[3];
+			this.right = o[4];
+			this.value = undefined;
+		}
+	}
+	solve(m, input) {
+		if (this.name === "humn") {
+			throw "unreachable humn";
+		}
+		if (this.value !== undefined) {
+			console.log (this.name, " = ", this.value);
+			return this.value;
+		}
+		switch(m) {
+		case this.up: return this.solveUp(input);
+		case this.left: return this.solveLeft(input);
+		case this.right: return this.solveRight(input);
+		default: throw "unreachable";
+		}
+	}
+	solveUp(input) {
+		if (this.name === "root") {
+			throw "unreachable";
+		}
+		const left = input[this.left].solve(this.name, input);
+		const right = input[this.right].solve(this.name, input);
+		console.log("UP\t", this.name, " = ", this.left, "(", left, ") ", this.operation, " ", this.right, " (", right, ")");
+		switch(this.operation) { // up = left op right
+		case "+": return left + right;
+		case "-": return left - right;
+		case "*": return left * right;
+		case "/": return left / right;
+		default: throw "unreachable";
+		}
+	}
+	solveLeft(input) {
+		if (this.name === "root") {
+			const root = input[this.right].solve(this.name, input);
+			console.log("root = ", root);
+			return root;
+		}
+		const up = input[this.up].solve(this.name, input);
+		const right = input[this.right].solve(this.name, input);
+		console.log("LEFT\t", this.name, "(", up, ") = ", this.left, this.operation, " ", this.right, " (", right, ")");
+		switch(this.operation) { // left = up invop right
+		case "+": return up - right;
+		case "-": return up + right;
+		case "*": return up / right;
+		case "/": return up * right;
+		default: throw "unreachable";
+		}
+	}
+	solveRight(input) {
+		if (this.name === "root") {
+			const root = input[this.left].solve(this.name, input);
+			console.log("root = ", root);
+			return root;
+		}
+		const up = input[this.up].solve(this.name, input);
+		const left = input[this.left].solve(this.name, input);
+		console.log("RIGHT\t", this.name, "(", up, ") = ", this.left, "(", left, ") ", this.operation, " ", this.right);
+		switch(this.operation) { // right = up invop right
+		case "+": return up - left;
+		case "-": return left - up;
+		case "*": return up / left;
+		case "/": return left / up;
+		default: throw "unreachable";
+		}
+	}
+	print() {
+		console.log(this.name, this.value);
+	}
+}
+
+function load(filename) {
+	let res = {};
+	fs.readFileSync(filename, "utf8")
+		.trim()
+		.split("\n")
+		.forEach(line => {
+			let m = new Monkey(line);
+			res[m.name] = m;
+		});
+	Object.values(res).forEach(m => {
+		if (m.value === undefined) {
+			res[m.right].up = m.name;
+			res[m.left].up = m.name;
+		}
+	});
+	return res;
+}
+
+let example = load("example");
+let input = load("input");
+
+function solve(input) {
+	let h = input["humn"];
+	return input[h.up].solve(h.name, input);
+}
+
+const exampleOutput = solve(example);
+if (exampleOutput !== 301n) {
+	console.log("Example failed with " + exampleOutput);
+	process.exit(1); // eslint-disable-line
+}
+
+console.log(solve(input));