AOC12

1 files changed, 90 insertions, 0 deletions

diff --git a/aoc12/src/main.rs b/aoc12/src/main.rs
new file mode 100644
index 0000000..bcd591c
--- /dev/null
+++ b/aoc12/src/main.rs
@@ -0,0 +1,90 @@
+extern crate regex;
+use regex::Regex;
+
+use std::io::BufReader;
+use std::io::prelude::*;
+use std::fs::File;
+
+
+fn main() {
+    let program = read_file();
+
+    let mut registers: [i32; 4] = [0;4];
+    registers[2] = 1; //init c to 1
+    let mut pc: usize = 0;
+
+    let cpy_lit = Regex::new(r"cpy ([-\d]+) (a|b|c|d)").unwrap();
+    let cpy_reg = Regex::new(r"cpy (a|b|c|d) (a|b|c|d)").unwrap();
+    let inc = Regex::new(r"inc (a|b|c|d)").unwrap();
+    let dec = Regex::new(r"dec (a|b|c|d)").unwrap();
+    let jnz_lit = Regex::new(r"jnz ([-\d]+) ([-\d]+)").unwrap();
+    let jnz_reg = Regex::new(r"jnz (a|b|c|d) ([-\d]+)").unwrap();
+
+    
+    while pc < program.len() {
+        let line = program[pc].as_ref();
+        let mut pc_next: usize = pc+1;
+        
+        if cpy_lit.is_match(line) {
+            let cap = cpy_lit.captures(line).unwrap();
+            let src: i32 = cap.at(1).unwrap().parse().unwrap();
+            let dest = to_register_index(cap.at(2).unwrap());
+            registers[dest] = src;
+        }
+        else if cpy_reg.is_match(line) {
+            let cap = cpy_reg.captures(line).unwrap();
+            let src = to_register_index(cap.at(1).unwrap());
+            let dest = to_register_index(cap.at(2).unwrap());
+            registers[dest] = registers[src];
+        }
+        else if inc.is_match(line) {
+            let cap = inc.captures(line).unwrap();
+            let dest = to_register_index(cap.at(1).unwrap());
+            registers[dest] = registers[dest] + 1;
+        }
+        else if dec.is_match(line) {
+            let cap = dec.captures(line).unwrap();
+            let dest = to_register_index(cap.at(1).unwrap());
+            registers[dest] = registers[dest] - 1;
+        }
+        else if jnz_lit.is_match(line) {
+            let cap = jnz_lit.captures(line).unwrap();
+            let condition: i32 = cap.at(1).unwrap().parse().unwrap();
+            let offset: i32 = cap.at(2).unwrap().parse().unwrap();
+            if condition != 0 {
+                pc_next = (pc as i32 + offset) as usize;
+            }
+        }
+        else if jnz_reg.is_match(line) {
+            let cap = jnz_reg.captures(line).unwrap();
+            let condition = to_register_index(cap.at(1).unwrap());
+            let offset: i32 = cap.at(2).unwrap().parse().unwrap();
+            if registers[condition] != 0 {
+                pc_next = (pc as i32 + offset) as usize;
+            }
+        }
+
+        pc = pc_next;
+    }
+    
+    println!("a: {}, b: {}, c: {}, d: {}", registers[0], registers[1], registers[2], registers[3]);
+    
+}
+
+fn to_register_index(name: &str) -> usize {
+    match name {
+        "a" => 0,
+        "b" => 1,
+        "c" => 2,
+        "d" => 3,
+        _ => panic!("Invalid register provided")
+    }
+}
+
+fn read_file() -> Vec<String> {
+    let file = BufReader::new(File::open("input.txt").unwrap());
+    file.lines()
+        .map(|line| line.unwrap().trim().to_string())
+        .filter(|line| line.len() > 0)
+        .collect()
+}