7.1 was a doosie

2022/7/index.js

@@ -0,0 +1,65 @@
+
+const fs = require('fs/promises');
+
+const createNode = (parent) => {
+  return {
+    parent,
+    children: {},
+    localSize: 0
+  };
+};
+
+let answer = 0;
+
+(async () => {
+  const input = await fs.readFile("./input.txt", 'utf8');
+
+  const lines = input.split("\n");
+
+  const files = createNode();
+
+  lines.reduce((node, line) => {
+    console.log("NODE: ", node);
+    const cd = line.match(/^\$ cd (.*)$/);
+    if(cd) {
+      console.log("CD: ", cd);
+      if(cd[1] == "..") {
+        return node.parent;
+      }
+      return node.children[cd[1]];
+    }
+    const dir = line.match(/^dir (.*)$/);
+    if(dir) {
+      console.log("DIR: ", dir);
+      node.children[dir[1]] = createNode(node);
+    }
+    const file = line.match(/^(\d+) .*$/);
+    if(file) {
+      node.localSize += parseFloat(file[1]);
+    }
+
+    return node;
+
+  }, files);
+
+  console.log("FILES: ", files);
+
+  const fullSize = totalSmallerDirs(files);
+
+  console.log("FULL SIZE: ", fullSize);
+  console.log("ANSWER: ", answer);
+
+})();
+
+const totalSmallerDirs = (node) => {
+  let totalSize =  node.localSize;
+
+  totalSize += sum(Object.values(node.children).map(totalSmallerDirs));
+
+  if(totalSize <= 100000) {
+    answer += totalSize;
+  }
+  return totalSize;
+}
+
+const sum = (arr) => arr.reduce((total, num) => total+num, 0);