day02 solution

day02/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "day02"
+version = "0.1.0"

day02/Cargo.toml

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+[package]
+name = "day02"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

day02/exampleInput.txt

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+A Y
+B X
+C Z

day02/src/main.rs

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+use std::fs;
+
+const DRAW_SCORE: i32 = 3;
+const WIN_SCORE: i32 = 6;
+const LOSE_SCORE: i32 = 0;
+
+fn read_file_to_string_list(file_path: &str) -> Vec<String> {
+    println!("Reading file {}", file_path);
+    let contents = fs::read_to_string(file_path).expect("Should have been able to read the file");
+    let mut splitted: Vec<String> = contents
+        .split("\n")
+        .into_iter()
+        .map(|s| s.to_string())
+        .collect();
+    splitted.pop();
+    return splitted;
+}
+
+enum WinState {
+    Win,
+    Loss,
+    Draw,
+    Error,
+}
+enum Shape {
+    Rock,
+    Paper,
+    Scissors,
+    Error,
+}
+
+fn is_win_for_right(left: &str, right: &str) -> WinState {
+    use crate::WinState::*;
+    match left {
+        // Rock
+        "A" => match right {
+            "X" => Draw,
+            "Y" => Win,
+            "Z" => Loss,
+            _ => Error,
+        },
+        // Paper
+        "B" => match right {
+            "X" => Loss,
+            "Y" => Draw,
+            "Z" => Win,
+            _ => Error,
+        },
+        // Scissors
+        "C" => match right {
+            "X" => Win,
+            "Y" => Loss,
+            "Z" => Draw,
+            _ => Error,
+        },
+        _ => return Error,
+    }
+}
+
+fn find_needed_shape_for_right(left: &str, win_state: WinState) -> String {
+    let shape = match win_state {
+        WinState::Loss => match left {
+            "A" => "Z",
+            "B" => "X",
+            "C" => "Y",
+            _ => "",
+        },
+        WinState::Win => match left {
+            "A" => "Y",
+            "B" => "Z",
+            "C" => "X",
+            _ => "",
+        },
+        WinState::Draw => match left {
+            "A" => "X",
+            "B" => "Y",
+            "C" => "Z",
+            _ => "",
+        },
+        WinState::Error => todo!(),
+    };
+    return String::from(shape);
+}
+
+fn find_complicated_result(left: &str, right: &str) -> i32 {
+    use crate::WinState::*;
+    let predetermined_win_state: WinState = match right {
+        "X" => Loss,
+        "Y" => Draw,
+        "Z" => Win,
+        _ => Error,
+    };
+    let needed_shape_for_right = find_needed_shape_for_right(left, predetermined_win_state);
+    return find_result(left, needed_shape_for_right.as_str());
+}
+
+fn find_result(left: &str, right: &str) -> i32 {
+    let shape_score = shape_score(string_to_shape(right));
+    match is_win_for_right(left, right) {
+        WinState::Win => return WIN_SCORE + shape_score,
+        WinState::Loss => return LOSE_SCORE + shape_score,
+        WinState::Draw => return DRAW_SCORE + shape_score,
+        WinState::Error => return 0,
+    }
+}
+fn shape_score(shape: Shape) -> i32 {
+    return match shape {
+        Shape::Rock => 1,
+        Shape::Paper => 2,
+        Shape::Scissors => 3,
+        Shape::Error => 0,
+    };
+}
+fn string_to_shape(shapestring: &str) -> Shape {
+    return match shapestring {
+        "A" | "X" => Shape::Rock,
+        "B" | "Y" => Shape::Paper,
+        "C" | "Z" => Shape::Scissors,
+        _ => Shape::Error,
+    };
+}
+
+fn main() {
+    let file_content = read_file_to_string_list("input.txt");
+    let mut results_first_part: Vec<i32> = vec![];
+    let mut results_second_part: Vec<i32> = vec![];
+    for line in &file_content {
+        let left_and_right: Vec<&str> = line.split(" ").collect();
+        results_first_part.push(find_result(left_and_right[0], left_and_right[1]));
+        results_second_part.push(find_complicated_result(
+            left_and_right[0],
+            left_and_right[1],
+        ));
+    }
+    let final_result_first_part: i32 = results_first_part.into_iter().sum();
+    println!("Final Result: {}", final_result_first_part);
+    let final_result_second_part: i32 = results_second_part.into_iter().sum();
+    println!("Final Result: {}", final_result_second_part)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_logic() {
+        assert_eq!(find_result("A", "Y"), 8);
+        assert_eq!(find_result("B", "X"), 1);
+        assert_eq!(find_result("C", "Z"), 6);
+    }
+    #[test]
+    fn test_second_part() {
+        assert_eq!(find_complicated_result("A", "Y"), 4);
+        assert_eq!(find_complicated_result("B", "X"), 1);
+        assert_eq!(find_complicated_result("C", "Z"), 7);
+    }
+}