From 80b0dea13be580bdcf71778d2ee275ad11e1e42f Mon Sep 17 00:00:00 2001
From: Andrew Ekstedt <andrew.ekstedt@gmail.com>
Date: Tue, 2 Dec 2025 05:54:52 +0000
Subject: [PATCH] day 2 part 1

---
 day02/input  |  1 +
 day02/sample |  1 +
 day02/sol.py | 40 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+)
 create mode 100644 day02/input
 create mode 100644 day02/sample
 create mode 100644 day02/sol.py

diff --git a/day02/input b/day02/input
new file mode 100644
index 0000000..fafb968
--- /dev/null
+++ b/day02/input
@@ -0,0 +1 @@
+2558912-2663749,1-19,72-85,82984-100358,86-113,193276-237687,51-69,779543-880789,13004-15184,2768-3285,4002-4783,7702278-7841488,7025-8936,5858546565-5858614010,5117615-5149981,4919-5802,411-466,126397-148071,726807-764287,7454079517-7454227234,48548-61680,67606500-67729214,9096-10574,9999972289-10000034826,431250-455032,907442-983179,528410-680303,99990245-100008960,266408-302255,146086945-146212652,9231222-9271517,32295166-32343823,32138-36484,4747426142-4747537765,525-652,333117-414840,13413537-13521859,1626-1972,49829276-50002273,69302-80371,8764571787-8764598967,5552410836-5552545325,660-782,859-1056
diff --git a/day02/sample b/day02/sample
new file mode 100644
index 0000000..a3f22ef
--- /dev/null
+++ b/day02/sample
@@ -0,0 +1 @@
+11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,446443-446449,38593856-38593862,565653-565659,824824821-824824827,2121212118-2121212124
diff --git a/day02/sol.py b/day02/sol.py
new file mode 100644
index 0000000..395d14f
--- /dev/null
+++ b/day02/sol.py
@@ -0,0 +1,40 @@
+def parse(s):
+    ret = []
+    for pair in s.split(','):
+        x,y = pair.split('-')
+        ret.append((int(x),int(y)))
+    return ret
+
+def solve(input):
+    with open(input) as f:
+        ranges = parse(f.read())
+
+    t = 0
+    for lo,hi in ranges:
+        invalid = list(findinvalid(lo,hi))
+        if len(invalid) == 0:
+            print(lo,hi,invalid)
+        t += sum(invalid)
+    print(t)
+
+def findinvalid(lo, hi):
+    assert len(str(hi)) - len(str(lo)) <= 1
+    assert lo <= hi
+    j = len(str(lo)) // 2
+    if j < 1:
+        # (1,19) => [11]
+        j = 1
+    for B in [10**j, 10**(j+1)]:
+        for i in range(lo//B, hi//B+1):
+            if i < B//10:
+                continue
+            if i >= B:
+                break
+            id = i*B + i
+            if lo <= id <= hi:
+                assert(str(i)+str(i) == str(id)), (i,id)
+                #print(lo, hi, i,B,id)
+                yield id
+
+#solve("sample")
+solve("input")