2022 day 7

2022/07/part2

@@ -0,0 +1,67 @@
+#!/usr/bin/env python
+
+import re
+from functools import reduce
+
+FS = {}
+POS = [] # empty dict is /
+
+def dig(d, keys):
+    if keys == []:
+        return d
+    else:
+        return reduce(dict.__getitem__, keys, d)
+
+def process_instruction(spec):
+    _, cmd, *args = spec.split(" ")
+    if cmd == "cd":
+        if args[0] == "/":
+            POS.clear()
+        elif args[0] == "..":
+            POS.pop()
+        else:
+            POS.append(args[0])
+    elif cmd != "ls": # nothing to do for ls
+        raise "Unknown command: " + spec
+
+def process_output(spec):
+    cwd = dig(FS, POS)
+    size_or_dir, name = spec.split(" ")
+
+    if size_or_dir == "dir":
+        cwd[name] = {}
+    else:
+        cwd[name] = int(size_or_dir)
+
+with open('input') as f:
+    # Read the diagram + separating line
+    for line in f:
+        if line[0] == '$':
+            process_instruction(line.rstrip())
+        else:
+            process_output(line.rstrip())
+
+SIZE = []
+
+# Recursively sum each dictionary and add the sums together
+def sum_sizes(d):
+    sz = 0
+
+    for v in d.values():
+        if isinstance(v, dict):
+          sz = sz + sum_sizes(v)
+        else:
+          sz = sz + v
+
+    SIZE.append(sz)
+
+    return sz
+
+total_used = sum_sizes(FS)
+space_free = 70000000 - total_used
+target = 30000000 - space_free
+
+for v in sorted(SIZE):
+    if v >= target:
+        print(v)
+        break