From f24f5b41487228a936d6195fcbf1fc84eea38b85 Mon Sep 17 00:00:00 2001
From: Allianzcortex <iamwanghz@gmail.com>
Date: Mon, 8 Dec 2025 10:52:47 -0500
Subject: [PATCH 1/2] add 2025 day8 solution

---
 README.md                                |  2 +
 advent_of_code/2025(python)/day8.py      | 53 ++++++++++++++++++++++++
 advent_of_code/2025(python)/test_day8.py | 36 ++++++++++++++++
 3 files changed, 91 insertions(+)
 create mode 100644 advent_of_code/2025(python)/day8.py
 create mode 100644 advent_of_code/2025(python)/test_day8.py

diff --git a/README.md b/README.md
index 9340644..65dcda8 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,8 @@ I also worked on [advent of code](https://adventofcode.com/) in the past years
 
 [advent of code 2024](./advent_of_code/2024(python)/)
 
+[advent of code 2025](./advent_of_code/2025(python)/)
+
 ---
 
 Here are python implementations for different ML/data-mining projects
diff --git a/advent_of_code/2025(python)/day8.py b/advent_of_code/2025(python)/day8.py
new file mode 100644
index 0000000..f27a858
--- /dev/null
+++ b/advent_of_code/2025(python)/day8.py
@@ -0,0 +1,53 @@
+sample_test_size = 10
+large_test_size = 1000
+
+
+class DSU:
+    def __init__(self, n):
+        self.p = list(range(n))
+        self.sz = [1] * n
+
+    def find(self, x):
+        if self.p[x] != x:
+            self.p[x] = self.find(self.p[x])
+        return self.p[x]
+
+    def union(self, a, b):
+        ra, rb = self.find(a), self.find(b)
+        if ra == rb:
+            return False
+        if self.sz[ra] < self.sz[rb]:
+            ra, rb = rb, ra
+        self.p[rb] = ra
+        self.sz[ra] += self.sz[rb]
+        return True
+
+
+def solve_day8_part1(input_):
+    input_ = [line.split(",") for line in input_]
+    distances = []
+
+    for i, line in enumerate(input_):
+        for j in range(i+1, len(input_)):
+            dis = get_distance(line, input_[j])
+            distances.append((dis, (i, j)))
+
+    distances.sort()
+
+    dsu = DSU(len(input_))
+    for i in range(sample_test_size):
+        _, (j, k) = distances[i]
+        dsu.union(j, k)
+
+    # get the largest 3 circles
+    roots = [dsu.sz[i] for i in range(len(input_)) if dsu.find(i) == i]
+    roots.sort(reverse=True)
+    return roots[0] * roots[1] * roots[2]
+
+
+def get_distance(line1, line2):
+    x_dis = int(line1[0])-int(line2[0])
+    y_dis = int(line1[1])-int(line2[1])
+    z_dis = int(line1[2])-int(line2[2])
+
+    return x_dis**2+y_dis**2+z_dis**2
diff --git a/advent_of_code/2025(python)/test_day8.py b/advent_of_code/2025(python)/test_day8.py
new file mode 100644
index 0000000..a8893ec
--- /dev/null
+++ b/advent_of_code/2025(python)/test_day8.py
@@ -0,0 +1,36 @@
+import unittest
+
+from day2 import solve_day8_part1
+
+question_input = [
+    "162,817,812",
+    "57,618,57",
+    "906,360,560",
+    "592,479,940",
+    "352,342,300",
+    "466,668,158",
+    "542,29,236",
+    "431,825,988",
+    "739,650,466",
+    "52,470,668",
+    "216,146,977",
+    "819,987,18",
+    "117,168,530",
+    "805,96,715",
+    "346,949,466",
+    "970,615,88",
+    "941,993,340",
+    "862,61,35",
+    "984,92,344",
+    "425,690,689",
+]
+
+
+class TestSample(unittest.TestCase):
+
+    def test_part1(self):
+        self.assertEqual(solve_day8_part1(question_input), 40)
+
+
+if __name__ == "__main__":
+    unittest.main()

From 283b6fd3f94554516392d773c7fdf10551c76e1d Mon Sep 17 00:00:00 2001
From: Allianzcortex <iamwanghz@gmail.com>
Date: Mon, 8 Dec 2025 10:55:23 -0500
Subject: [PATCH 2/2] fix test import

---
 advent_of_code/2025(python)/test_day8.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/advent_of_code/2025(python)/test_day8.py b/advent_of_code/2025(python)/test_day8.py
index a8893ec..46c801a 100644
--- a/advent_of_code/2025(python)/test_day8.py
+++ b/advent_of_code/2025(python)/test_day8.py
@@ -1,6 +1,6 @@
 import unittest
 
-from day2 import solve_day8_part1
+from day8 import solve_day8_part1
 
 question_input = [
     "162,817,812",