Add solution to day 2 in rust

day2/rs/main.rs

@@ -0,0 +1,90 @@
+use std::fs;
+use std::process;
+
+const DESIRED_RESULT: i32 = 19690720;
+
+enum Opcode {
+	Add = 1,
+	Mult  = 2,
+	Terminate = 99
+}
+
+#[derive(Clone)]
+struct Program {
+	memory: Vec<i32>
+}
+
+impl Program {
+	fn execute(&self, param1: i32, param2: i32) -> Result<i32, String> {
+		let mut local_memory = self.memory.clone();
+		local_memory[1] = param1;
+		local_memory[2] = param2;
+		for i in (0..local_memory.len()).step_by(4) {
+			let item = local_memory[i];
+			let operation = match item {
+				item if item == Opcode::Add as i32 => {
+					std::ops::Add::add
+				},
+				item if item == Opcode::Mult as i32 => {
+					std::ops::Mul::mul
+				},
+				item if item == Opcode::Terminate as i32 => {
+					 break;
+				},
+				_ => {
+					return Err("Bad Opcode".to_string());
+				}
+			};
+
+			let param_a_index = local_memory[i + 1] as usize;
+			let param_b_index = local_memory[i + 2] as usize;
+			let out_index = local_memory[i + 3] as usize;
+			local_memory[out_index] = operation(local_memory[param_a_index], local_memory[param_b_index])
+		}
+
+		return Ok(local_memory[0])
+	}
+}
+
+fn part1(program: &Program) -> Result<i32, String> {
+	program.execute(12, 2)
+}
+
+fn part2(program: &Program) -> Result<(i32, i32), String> {
+	for i in 0..100 {
+		for j in 0..100 {
+			let result = program.execute(i, j)?;
+			if result == DESIRED_RESULT {
+				return Ok((i, j))
+			}
+		}
+	}
+
+	Err("Could not find result".to_string())
+}
+
+fn main() {
+	let raw_input = fs::read_to_string("../input.txt");
+	let input = match &raw_input {
+		Ok(contents) => contents
+			.trim()
+			.split(',')
+			.map(|x| { x.parse::<i32>().unwrap() })
+			.collect::<Vec<_>>(),
+		Err(error) => {
+			eprintln!("Could not read input: {}", error);
+			process::exit(1)
+		}
+	};
+	let program = Program{memory: input};
+
+	match part1(&program) {
+		Ok(result) => println!("{}", result),
+		Err(error) => println!("{}", error)
+	}
+
+	match part2(&program) {
+		Ok(result) => println!("{:?}", result),
+		Err(error) => println!("{}", error)
+	}
+}