From 448f1d209ff0aa8b4f2756bf2caca997a02afd18 Mon Sep 17 00:00:00 2001
From: Fabian Schmidt <fabschmidt96@gmail.com>
Date: Mon, 16 Sep 2024 12:42:55 +0200
Subject: [PATCH] solved 28

---
 src/bin/problem_28.rs | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 src/bin/problem_28.rs

diff --git a/src/bin/problem_28.rs b/src/bin/problem_28.rs
new file mode 100644
index 0000000..6bd0b96
--- /dev/null
+++ b/src/bin/problem_28.rs
@@ -0,0 +1,19 @@
+// instead of computing the spiral and summing the diagonals, only get corners
+fn main() {
+    let dimension = 1001;
+    let mut sum = 0;
+    let squares = (dimension / 2) + 1;
+    let mut last_square_end = 0;
+    for square in 0..squares {
+        if square == 0 {
+            sum = 1;
+            last_square_end = 1;
+            continue;
+        }
+        for corner in 0..4 {
+            sum += last_square_end + (square * 2) * (corner + 1);
+        }
+        last_square_end = last_square_end + (square * 2) * 4;
+    }
+    println!("{sum}");
+}