day one part one

one/.gitignore

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+/target

one/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "one"
+version = "0.1.0"

one/Cargo.toml

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

one/output

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+54304

one/src/main.rs

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+use std::io::{self, Read};
+
+fn main() {
+    let mut buf = String::new();
+    io::stdin().read_to_string(&mut buf).unwrap();
+
+    let lines: Vec<String> = buf.lines().map(ToOwned::to_owned).collect();
+
+    let answer: Result<i32, _> = lines
+        .into_iter()
+        .map(|l| l.chars().filter(char::is_ascii_digit).collect())
+        .map(|s: String| [s.chars().next().unwrap(), s.chars().last().unwrap()].to_owned())
+        .map(String::from_iter)
+        .map(|s| s.parse::<i32>())
+        .sum();
+
+    let answer = answer.unwrap();
+
+    print!("{answer}");
+}