1 files changed, 126 insertions, 0 deletions
diff --git a/day-7/index.ts b/day-7/index.ts
new file mode 100644
index 0000000..689e647
--- /dev/null
+++ b/day-7/index.ts
@@ -0,0 +1,126 @@
+import fs from "fs";
+
+const file = fs.readFileSync("./input.txt").toString();
+
+const lines = file.split("\n").filter((x) => x.length);
+
+// File or Directory
+interface Item {
+  type: "dir" | "file";
+  name: string;
+  size: number;
+}
+
+interface CommandWithOutput {
+  command: string;
+  outputs: Item[];
+}
+
+interface CommandWithDir extends CommandWithOutput {
+  directory: string[];
+}
+
+function isCommandString(s: string) {
+  return s.startsWith("$");
+}
+
+function parseLines(lines: string[]): CommandWithOutput[] {
+  return lines.reduce((acc, current, index) => {
+    if (isCommandString(current)) {
+      const nextCommandIndex =
+        lines.slice(index + 1).findIndex(isCommandString) + index + 1;
+
+      const smartIndex =
+        nextCommandIndex === index ? lines.length : nextCommandIndex;
+      const outputs = lines.slice(index + 1, smartIndex).map((line) => {
+        const dirMatch = line.match(/dir (.*)/);
+        const fileMatch = line.match(/(.*) (.*)/);
+
+        if (dirMatch && dirMatch[1])
+          return {
+            type: "dir",
+            size: 0,
+            name: dirMatch[1],
+          } satisfies Item;
+        if (fileMatch)
+          return {
+            type: "file",
+            size: Number(fileMatch[1]),
+            name: fileMatch[2],
+          } satisfies Item;
+        throw new Error("Unhandled");
+      });
+      acc.push({ outputs, command: current });
+    }
+    return acc;
+  }, [] as CommandWithOutput[]);
+}
+
+function computeDirectories(commands: CommandWithOutput[]): CommandWithDir[] {
+  return commands.reduce((acc, current) => {
+    const previousDir = acc[acc.length - 1]?.directory;
+
+    const match = current.command.match(/\$ cd (.*)/);
+    const directory = match
+      ? previousDir
+        ? match[1] !== ".."
+          ? [...previousDir, match[1]]
+          : [...previousDir.slice(0, -1)]
+        : [match[1]]
+      : [...previousDir];
+
+    acc.push({ ...current, directory });
+    return acc;
+  }, [] as CommandWithDir[]);
+}
+
+const parsed = parseLines(lines);
+const withDirs = computeDirectories(parsed);
+const lsOutputs = withDirs.filter((cmd) => cmd.command === "$ ls");
+
+// DIRTY CODE STARTS HERE
+function computeDirSize(
+  cmd: CommandWithDir & { totalSize: number | undefined },
+) {
+  if (cmd.totalSize !== undefined) return;
+  cmd.outputs
+    .filter((f) => f.type === "dir")
+    .forEach((dir) => {
+      const path = [...cmd.directory, dir.name];
+      const dirNode = data.find(
+        (datum) => JSON.stringify(datum.directory) === JSON.stringify(path),
+      );
+
+      if (!dirNode) throw new Error(`Unknown size ${dir.name}`);
+      if (dirNode.totalSize === undefined) {
+        computeDirSize(dirNode);
+      }
+      if (dirNode.totalSize !== undefined) {
+        dir.size = dirNode.totalSize;
+      } else {
+        throw new Error(
+          `${dir.name}, ${JSON.stringify(path)}, ${JSON.stringify(dirNode)}`,
+        );
+      }
+    });
+
+  const totalSize = cmd.outputs.reduce((sum, f) => sum + f.size, 0);
+
+  cmd.totalSize = totalSize;
+  // console.log("Setting size ", totalSize, " to dir", cmd.directory);
+}
+
+const data = lsOutputs.map((o) => ({
+  ...o,
+  totalSize: undefined as undefined | number,
+}));
+
+data.forEach(computeDirSize);
+console.log(data);
+
+const sum = data
+  .filter((d) => d.totalSize)
+  .filter((datum) => (datum?.totalSize || 0) <= 100_000)
+  .reduce((acc, d) => acc + (d?.totalSize || 0), 0);
+
+console.log(sum);