Add day 2 part 1 in Rust

2019/02/day2.rs

@@ -0,0 +1,37 @@
+use std::io;
+use std::io::BufRead;
+
+pub fn main() {
+    let input: Vec<usize> = io::stdin()
+        .lock()
+        .lines()
+        .next()
+        .unwrap()
+        .unwrap()
+        .split(',')
+        .map(|n| n.parse().unwrap())
+        .collect();
+    println!("Part 1: {}", execute(&mut input.clone(), 12, 2));
+}
+
+fn execute(input: &mut Vec<usize>, p1: usize, p2: usize) -> usize {
+    input[1] = p1;
+    input[2] = p2;
+    for i in (0..).step_by(4) {
+        let opcode = input[i];
+        let first = input[i+1];
+        let second = input[i+2];
+        let target = input[i+3];
+        if target == 0 {
+            dbg!("target is 0", target, opcode, first, second);
+        }
+        match opcode {
+            1 => input[target] = input[first] + input[second],
+            2 => input[target] = input[first] * input[second],
+            99 => break,
+            _ => unreachable!("Invalid opcode")
+        }
+    }
+    dbg!(&input);
+    input[0]
+}