Add 2022 day 1

2022/1/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "day1"
+version = "0.1.0"

2022/1/Cargo.toml

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+[package]
+name = "day1"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

2022/1/src/main.rs

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+use std::cmp::Ordering;
+use std::str::FromStr;
+
+fn main() {
+
+    let mut input_file = Some("input".to_string());
+    let mut args = std::env::args();
+    while args.len() > 0 {
+        let arg = args.nth(0);
+        if arg.unwrap().eq("-f") {
+            let value = args.nth(0);
+            if value.is_some() {
+                input_file = value;
+            }
+            else {
+                println!("No value after argument: '-f'");
+            }
+        }
+    }
+    println!("Input file: '{:?}'", input_file);
+    let mut elves = elves_from_file(&input_file.unwrap()).expect("failed to read file");
+    elves.sort_by(|a, b| b.cmp_by_calories(a));
+    println!("[PART 1] Elf with most calories: {}", elves[0].calories());
+
+    let p2_elves: std::vec::Vec::<_> = elves.into_iter()
+        .enumerate()
+        .filter(|&(i, _)| i < 3 )
+        .map(|(_, e)| e)
+        .collect();
+    let mut p2_calories: u32 = 0;
+    for x in p2_elves {
+        p2_calories += x.calories();
+    }
+    println!("[PART 2] Top 3 elves have these calories: {}", p2_calories);
+}
+
+struct Elf {
+    items: std::vec::Vec<u32>,
+}
+
+impl Elf {
+    fn calories(&self) -> u32 {
+        let mut value = 0;
+        for x in &self.items {
+            value += x;
+        }
+        return value;
+    }
+
+    fn cmp_by_calories(&self, b: &Elf) -> Ordering {
+        return self.calories().cmp(&b.calories());
+    }
+}
+
+fn elves_from_file(file_name: &String) -> std::result::Result<std::vec::Vec::<Elf>, String> {
+    let contents = std::fs::read_to_string(file_name).expect("Couldn't read contents of file");
+    return std::result::Result::Ok(elves_from_string(&contents));
+}
+
+fn elves_from_string(contents: &String) -> std::vec::Vec::<Elf> {
+    let mut elves = std::vec::Vec::<Elf>::new();
+    let mut current_elf = Elf {
+        items: std::vec::Vec::<u32>::new(),
+    };
+    for line in contents.lines() {
+        if line.eq("") {
+            elves.push(current_elf);
+            current_elf = Elf {
+                items: std::vec::Vec::<u32>::new(),
+            };
+        }
+        else {
+            match u32::from_str(&line) {
+                Ok(v) => {
+                    current_elf.items.push(v);
+                },
+                Err(_) => {
+                    println!("WARNING: '{}' does not convert to u32, skipping.", line);
+                    continue;
+                },
+            }
+        }
+    }
+    if current_elf.items.len() > 0 {
+        elves.push(current_elf);
+    }
+    return elves;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_from_empty_string() {
+        let contents = "".to_string();
+        let elves = elves_from_string(&contents);
+        assert_eq!(elves.len(), 0);
+    }
+
+    #[test]
+    fn test_from_string() {
+        let contents = r#"1000
+2000
+3000
+
+4000
+
+5000
+6000
+
+7000
+8000
+9000
+
+10000
+"#.to_string();
+        let elves = elves_from_string(&contents);
+        assert_eq!(elves.len(), 5);
+        let first = vec![1000, 2000, 3000];
+        assert!(first.eq(&elves[0].items));
+        let last = vec![10000];
+        assert!(last.eq(&elves[4].items));
+    }
+
+    #[test]
+    fn test_calories() {
+        let mut elf = Elf {
+            items: std::vec::Vec::<u32>::new(),
+        };
+        assert_eq!(elf.calories(), 0);
+
+        elf.items.push(1000);
+        elf.items.push(10000);
+
+        assert_eq!(elf.calories(), 11000);
+    }
+
+    #[test]
+    fn test_sort() {
+        let mut v = std::vec::Vec::<Elf>::new();
+        v.push(Elf {
+            items: vec![5000, 50000],
+        });
+        v.push(Elf {
+            items: vec![1000, 10000],
+        });
+        assert_eq!(v[0].calories(), 55000);
+        v.sort_by(|a, b| a.cmp_by_calories(b));
+        assert_eq!(v[0].calories(), 11000);
+    }
+}