From a47d72f8cca66b1c96be02069c1407d53d31b48c Mon Sep 17 00:00:00 2001
From: "Dr. Matthias Ratajczak" <m.ratajczak@hzdr.de>
Date: Tue, 20 Jun 2023 14:53:17 +0200
Subject: [PATCH] add 92

---
 src/euler92/Cargo.toml  |  9 +++++++++
 src/euler92/src/main.rs | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+)
 create mode 100644 src/euler92/Cargo.toml
 create mode 100644 src/euler92/src/main.rs

diff --git a/src/euler92/Cargo.toml b/src/euler92/Cargo.toml
new file mode 100644
index 0000000..93ea1b7
--- /dev/null
+++ b/src/euler92/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "euler92"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[profile.release]
+lto = "fat"
diff --git a/src/euler92/src/main.rs b/src/euler92/src/main.rs
new file mode 100644
index 0000000..24c4785
--- /dev/null
+++ b/src/euler92/src/main.rs
@@ -0,0 +1,38 @@
+const MAXIMUM: usize = 10_000_000;
+
+fn main() {
+    let mut arrives_at_89 = 0;
+
+    for i in 1..MAXIMUM {
+        let mut number = i;
+        loop {
+            let sum: usize = number
+                .to_digits()
+                .into_iter()
+                .map(|d| d.pow(2) as usize)
+                .sum();
+            if sum == 89 {
+                arrives_at_89 += 1;
+                break;
+            } else if sum == 1 {
+                break;
+            }
+            number = sum;
+        }
+    }
+
+    println!("{arrives_at_89}");
+}
+
+trait ToDigits {
+    fn to_digits(&self) -> Vec<u8>;
+}
+
+impl ToDigits for usize {
+    fn to_digits(&self) -> Vec<u8> {
+        self.to_string()
+            .chars()
+            .map(|c| c.to_digit(10).unwrap() as _)
+            .collect()
+    }
+}