Finished PE 092 with brute force, not hard

projecteuler/092/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "main"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

projecteuler/092/src/main.rs

@@ -0,0 +1,42 @@
+use std::collections::HashSet;
+use std::time::Instant;
+
+fn square_digits(n: u32) -> u32 {
+    let mut result = 0;
+    let mut n = n;
+
+    while n > 0 {
+        result += (n % 10).pow(2);
+        n /= 10;
+    }
+
+    return result;
+}
+
+fn main() {
+    println!("Hello, this is Patrick!");
+    let now = Instant::now();
+
+    const MAX_INT: u32 = 10000000;
+
+    let mut loop_1 = HashSet::new();
+    let mut loop_89 = HashSet::new();
+
+    for n in 1..MAX_INT {
+        let mut m = n;
+        loop {
+            if loop_1.contains(&m) || m == 1 {
+                loop_1.insert(n);
+                break;
+            } else if loop_89.contains(&m) || m == 89 {
+                loop_89.insert(n);
+                break;
+            } else {
+                m = square_digits(m);
+            }
+        }
+    }
+
+    println!("Number of numbers that end in 89-loop: {}", loop_89.len());
+    println!("Time passed: {:?}", Instant::now() - now);
+}