Solve 2025-11

2025/11/2025-11.run.xml

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+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="2025-11" type="BunRunConfiguration">
+    <option name="program" value="2025/11/run.ts" />
+    <option name="workingDirectory" value="$PROJECT_DIR$" />
+    <method v="2" />
+  </configuration>
+</component>

2025/11/index.test.ts

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+import { describe, expect, it } from 'bun:test';
+import { solveFirst, solveSecond } from './index.ts';
+
+describe('2025-11', () => {
+  it('first', () => {
+    const testInput = `aaa: you hhh
+you: bbb ccc
+bbb: ddd eee
+ccc: ddd eee fff
+ddd: ggg
+eee: out
+fff: out
+ggg: out
+hhh: ccc fff iii
+iii: out`;
+    expect(solveFirst(testInput)).toBe(5);
+  });
+  it('second', () => {
+    const testInput = `svr: aaa bbb
+aaa: fft
+fft: ccc
+bbb: tty
+tty: ccc
+ccc: ddd eee
+ddd: hub
+hub: fff
+eee: dac
+dac: fff
+fff: ggg hhh
+ggg: out
+hhh: out`;
+    expect(solveSecond(testInput)).toBe(2);
+  });
+});

2025/11/index.ts

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+import { sumArray } from '../../utils/array.ts';
+
+function parseInput(input: string) {
+  return input.split('\n').map((row) => {
+    const [from, _to] = row.split(': ');
+
+    return { from, to: _to.split(' ') };
+  });
+}
+
+function dfs(
+  start: string,
+  target: string,
+  graph: ReturnType<typeof parseInput>,
+  memo: Map<string, number> = new Map<string, number>()
+) {
+  if (start === target) {
+    return 1;
+  }
+  if (memo.has(start)) {
+    return memo.get(start)!;
+  }
+  const val = sumArray(
+    graph
+      .find((r) => r.from === start)
+      ?.to?.map((to) => dfs(to, target, graph, memo)) || [0]
+  );
+  memo.set(start, val);
+
+  return val;
+}
+
+export function solveFirst(input: string): number {
+  const rows = parseInput(input);
+
+  return dfs('you', 'out', rows);
+}
+
+export function solveSecond(input: string): number {
+  const rows = parseInput(input);
+
+  const svr_fft = dfs('svr', 'fft', rows);
+  const fft_dac = dfs('fft', 'dac', rows);
+  const dac_out = dfs('dac', 'out', rows);
+
+  const svr_dac = dfs('svr', 'dac', rows);
+  const dac_fft = dfs('dac', 'fft', rows);
+  const fft_out = dfs('fft', 'out', rows);
+
+  return svr_fft * fft_dac * dac_out + svr_dac * dac_fft * fft_out;
+}

2025/11/run.ts

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+import { join } from 'path';
+import { solveFirst, solveSecond } from './index.ts';
+
+const input = await Bun.file(join(__dirname, 'input.txt')).text();
+
+const firstAnswer = solveFirst(input);
+
+console.log(firstAnswer);
+
+const secondAnswer = solveSecond(input);
+
+console.log(secondAnswer);