2025/day-06: Solve part 1

2025/rust/day-06/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "day-06"
+version = "0.1.0"

2025/rust/day-06/Cargo.toml

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+[package]
+name = "day-06"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

2025/rust/day-06/src/main.rs

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+use std::{fmt::Debug, fs};
+
+#[derive(PartialEq, Debug)]
+enum Operation {
+    Add,
+    Multiply,
+}
+
+#[derive(Debug)]
+struct Problem {
+    numbers: Vec<u64>,
+    operation: Operation,
+}
+
+impl Problem {
+    fn solve(&self) -> u64 {
+        if self.operation == Operation::Add {
+            self.numbers.iter().sum()
+        } else {
+            self.numbers.iter().product()
+        }
+    }
+}
+
+fn main() {
+    let problems = parse_input(&fs::read_to_string("../../inputs/06.txt").unwrap());
+
+    println!("Grand total: {}", grand_total(&problems));
+}
+
+fn parse_input(contents: &str) -> Vec<Problem> {
+    let grid: Vec<Vec<&str>> = contents
+        .trim()
+        .lines()
+        .map(|line| line.split_whitespace().collect())
+        .collect();
+
+    let mut list: Vec<Problem> = Vec::new();
+
+    for (col, _) in grid[0].iter().enumerate() {
+        let mut numbers: Vec<u64> = Vec::new();
+
+        let operation = match grid[grid.len() - 1][col] {
+            "+" => Operation::Add,
+            "*" => Operation::Multiply,
+            _ => panic!("Unsupported Operation"),
+        };
+
+        for (row, _) in grid[..grid.len() - 1].iter().enumerate() {
+            numbers.push(grid[row][col].parse().unwrap());
+        }
+
+        list.push(Problem { numbers, operation });
+    }
+
+    list
+}
+
+fn grand_total(problems: &[Problem]) -> u64 {
+    problems.iter().map(Problem::solve).sum()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const TEST_INPUT: &str = "
+123 328  51 64 
+ 45 64  387 23 
+  6 98  215 314
+*   +   *   +  ";
+
+    #[test]
+    fn test_part1() {
+        assert_eq!(grand_total(&parse_input(TEST_INPUT)), 4277556);
+    }
+}