From 55cb5ed745a5ffc9fe6384bbcfc2a0c5f971ddc3 Mon Sep 17 00:00:00 2001
From: Mikael CAPELLE <capelle.mikael@gmail.com>
Date: Wed, 4 Dec 2024 09:31:47 +0100
Subject: [PATCH] Refactor 2024 day 4.

---
 src/holt59/aoc/2024/day4.py | 57 ++++++++++++++-----------------------
 1 file changed, 21 insertions(+), 36 deletions(-)

diff --git a/src/holt59/aoc/2024/day4.py b/src/holt59/aoc/2024/day4.py
index 64188be..656ed2e 100644
--- a/src/holt59/aoc/2024/day4.py
+++ b/src/holt59/aoc/2024/day4.py
@@ -1,45 +1,30 @@
+import itertools as it
 import sys
 
-import numpy as np
+lines = sys.stdin.read().strip().splitlines()
+n = len(lines)
 
-lines = np.array(list(map(list, sys.stdin.read().strip().splitlines())))
-print(lines)
-n = lines.shape[0]
-
-answer_1 = 0
-for i in range(n):
-    line = "".join(lines[i, :])
-    answer_1 += line.count("XMAS") + line.count("SAMX")
-
-    column = "".join(lines[:, i])
-    answer_1 += column.count("XMAS") + column.count("SAMX")
-
-    diag = "".join(np.diagonal(lines, i))
-    answer_1 += diag.count("XMAS") + diag.count("SAMX")
-
-    diag = "".join(np.diagonal(lines[::-1, :], i))
-    answer_1 += diag.count("XMAS") + diag.count("SAMX")
-
-    if i != 0:
-        diag = "".join(np.diagonal(lines, -i))
-        answer_1 += diag.count("XMAS") + diag.count("SAMX")
-
-        diag = "".join(np.diagonal(lines[::-1, :], -i))
-        answer_1 += diag.count("XMAS") + diag.count("SAMX")
+answer_1 = sum(
+    line.count("XMAS") + line.count("SAMX")
+    for i in range(n)
+    for ri, rk, ro, ci, ck, cm in (
+        (1, 0, 0, 0, 1, n),
+        (0, 1, 0, 1, 0, n),
+        (0, 1, 0, 1, 1, n - i),
+        (0, -1, -1, 1, 1, n - i),
+        (1, 1, 0, 0, 1, n - i if i != 0 else 0),
+        (-1, -1, -1, 0, 1, n - i if i != 0 else 0),
+    )
+    if (
+        line := "".join(lines[ri * i + rk * k + ro][ci * i + ck * k] for k in range(cm))
+    )
+)
 
 answer_2 = sum(
-    "".join(
-        (
-            lines[i - 1, j - 1],
-            lines[i - 1, j + 1],
-            lines[i + 1, j - 1],
-            lines[i + 1, j + 1],
-        )
-    )
+    lines[i][j] == "A"
+    and "".join(lines[i + di][j + dj] for di, dj in it.product((-1, 1), (-1, 1)))
     in {"MSMS", "SSMM", "MMSS", "SMSM"}
-    for i in range(1, n - 1)
-    for j in range(1, n - 1)
-    if lines[i, j] == "A"
+    for i, j in it.product(range(1, n - 1), range(1, n - 1))
 )
 
 print(f"answer 1 is {answer_1}")