day07: add solutions

Author: tfaughnan

day07/1.py

@@ -0,0 +1,26 @@
+#!/usr/bin/env pypy3
+
+import os.path
+import re
+import sys
+
+SIZE_BOUND = 100000
+
+def main():
+    dirsizes = {}
+    cwd = '/'
+    for line in sys.stdin:
+        if m := re.match(r'^\$ cd \.\.$', line):
+            cwd, _ = os.path.split(cwd)
+        elif m := re.match(r'^\$ cd (\S+)$', line):
+            cwd = os.path.join(cwd, m.group(1))
+            dirsizes[cwd] = 0
+        elif m := re.match(r'^([0-9]+) (\S+)$', line):
+            size = int(m.group(1))
+            for d in filter(cwd.startswith, dirsizes):
+                dirsizes[d] += size
+
+    print(sum(v for v in dirsizes.values() if v <= SIZE_BOUND))
+
+if __name__ == '__main__':
+    main()

day07/2.py

@@ -0,0 +1,28 @@
+#!/usr/bin/env pypy3
+
+import os.path
+import re
+import sys
+
+SIZE_DISK = 70000000
+SIZE_NEED = 30000000
+
+def main():
+    dirsizes = {}
+    cwd = '/'
+    for line in sys.stdin:
+        if m := re.match(r'^\$ cd \.\.$', line):
+            cwd, _ = os.path.split(cwd)
+        elif m := re.match(r'^\$ cd (\S+)$', line):
+            cwd = os.path.join(cwd, m.group(1))
+            dirsizes[cwd] = 0
+        elif m := re.match(r'^([0-9]+) (\S+)$', line):
+            size = int(m.group(1))
+            for d in filter(cwd.startswith, dirsizes):
+                dirsizes[d] += size
+
+    size_to_delete = SIZE_NEED - (SIZE_DISK - dirsizes['/'])
+    print(min(v for v in dirsizes.values() if v >= size_to_delete))
+
+if __name__ == '__main__':
+    main()