Day 5 2025

3 files changed, 47 insertions, 2 deletions

diff --git a/2025/05/a.py b/2025/05/a.py
index 5fdb11b..b2699ba 100644
--- a/2025/05/a.py
+++ b/2025/05/a.py
@@ -1,6 +1,17 @@
 import fileinput
 
+rang = True
+ranges = []
+s = 0
 with fileinput.input() as lines:
         for line in lines:
-                ...
-
+                if line == '\n':
+                        rang = False
+                elif rang:
+                        i = line.find('-')
+                        ranges.append((int(line[:i]), int(line[i+1:-1])))
+                else:
+                        x = int(line[:-1])
+                        if any(x >= r[0] and x <= r[1] for r in ranges):
+                                s += 1
+print(s)
diff --git a/2025/05/b.py b/2025/05/b.py
new file mode 100644
index 0000000..09bc5e4
--- /dev/null
+++ b/2025/05/b.py
@@ -0,0 +1,26 @@
+import fileinput
+
+def overlap(r1, r2):
+        return min(r1[1], r2[1]) >= max(r1[0], r2[0])
+
+def fuse(r1, r2):
+        return (min(r1[0], r2[0]), max(r1[1], r2[1]))
+
+ranges = []
+with fileinput.input() as lines:
+        for line in lines:
+                if line == '\n':
+                        break
+                i = line.find('-')
+                ranges.append((int(line[:i]), int(line[i+1:-1])))
+
+s = set()
+for r in ranges:
+        c = r
+        for rr in list(s):
+                if overlap(c, rr):
+                        c = fuse(c, rr)
+                        s.remove(rr)
+        s.add(c)
+
+print(sum(r[1] - r[0] + 1 for r in s))
diff --git a/2025/README.md b/2025/README.md
index 8fccef4..a77c168 100644
--- a/2025/README.md
+++ b/2025/README.md
@@ -11,6 +11,7 @@ Example
 
 ```
 Day   -Part 1-   -Part 2-
+  5   00:04:39   00:22:19
   4   00:25:36   00:27:49
   3   00:05:02   00:16:09
   2   00:10:36   00:11:55
@@ -61,3 +62,10 @@ out of bounds.
 
 For part 2 I decided to quickly code the dumb "repeat part 1 until no
 rolls are removed" strategy and it worked.
+
+### Day 5: Cafeteria
+
+Part 2 required a little bit of thinking to handle overlaps correctly
+- at first I wrote a solution that did not handle overlaps, then one
+that can only handle single overlaps, and finally one that works in
+every case. My final solution is quite straightforward.