Add solutions for day 16

day-16/Sample.mjs

@@ -0,0 +1,22 @@
+import operations from './operations';
+
+const DEFINITION_REGEXP = /\d+/g;
+
+class Sample {
+  constructor(definition) {
+    const numbers = definition.match(DEFINITION_REGEXP).map(Number);
+    this.before = numbers.slice(0, 4);
+    [this.opcode, this.inputA, this.inputB, this.outputC] = numbers.slice(4, 8);
+    this.after = numbers.slice(8);
+  }
+
+  probe() {
+    return operations.filter((operation) => {
+      const data = [].concat(this.before);
+      operation(data, this.inputA, this.inputB, this.outputC);
+      return data.toString() === this.after.toString();
+    });
+  }
+}
+
+export default Sample;

day-16/index.mjs

@@ -0,0 +1,42 @@
+#!/usr/bin/env node --experimental-modules --no-warnings
+
+import Sample from './Sample';
+import input from './input';
+import operations from './operations';
+import { day } from '../utils';
+
+const [sampling, program] = input.split('\n\n\n\n');
+const samples = sampling.split('\n\n').map(definition => new Sample(definition));
+
+day(16).part(1).solution(() => (
+  samples.filter(sample => (
+    sample.probe().length >= 3
+  )).length
+));
+
+day(16).part(2).solution(() => {
+  const remaining = new Set(samples);
+  while (remaining.size) {
+    for (const sample of remaining) {
+      const candidates = sample.probe().filter(operation => (
+        operation.opcode === undefined
+      ));
+      if (candidates.length === 1) {
+        const [operation] = candidates;
+        operation.opcode = sample.opcode;
+      }
+      if (candidates.length <= 1) {
+        remaining.delete(sample);
+      }
+    }
+  }
+
+  const data = [0, 0, 0, 0];
+  const lines = program.split('\n');
+  for (const line of lines) {
+    const [opcode, inputA, inputB, outputC] = line.match(/\d+/g).map(Number);
+    const operation = operations.find(candidate => candidate.opcode === opcode);
+    operation(data, inputA, inputB, outputC);
+  }
+  return data[0];
+});

day-16/input/example.mjs

@@ -0,0 +1,6 @@
+export default `Before: [3, 2, 1, 1]
+9 2 1 2
+After:  [3, 2, 2, 1]
+
+
+9 1 1 1`;