40

src/euler40/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "euler40"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

src/euler40/src/main.rs

@@ -0,0 +1,23 @@
+fn main() {
+    let mut s = String::new();
+    let mut i = 0;
+    loop {
+        s.push_str(&i.to_string());
+        i += 1;
+        if s.len() > 1_000_000 {
+            break;
+        }
+    }
+
+    let mut result = 1;
+    for i in [1, 10, 100, 1_000, 10_000, 100_000, 1_000_000] {
+        result *= s
+            .chars()
+            .nth(i)
+            .unwrap()
+            .to_string()
+            .parse::<usize>()
+            .unwrap();
+    }
+    println!("{result}")
+}