diff --git a/Cargo.toml b/Cargo.toml
index d8be311..ad2002f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -24,4 +24,8 @@ path = "src/day4/main.rs"
 
 [[bin]]
 name = "day5"
-path = "src/day5/main.rs"
\ No newline at end of file
+path = "src/day5/main.rs"
+
+[[bin]]
+name = "day7"
+path = "src/day7/main.rs"
\ No newline at end of file
diff --git a/src/day7/main.rs b/src/day7/main.rs
new file mode 100644
index 0000000..aa3543b
--- /dev/null
+++ b/src/day7/main.rs
@@ -0,0 +1,354 @@
+use std::collections::VecDeque;
+use std::env;
+use std::fs::File;
+use std::io::{self, BufRead, BufReader};
+
+#[derive(Copy, Clone, Debug)]
+enum Mode {
+    Position,
+    Immediate,
+}
+
+impl Default for Mode {
+    fn default() -> Self {
+        Mode::Position
+    }
+}
+
+impl From<bool> for Mode {
+    fn from(b: bool) -> Self {
+        match b {
+            false => Mode::Position,
+            true => Mode::Immediate,
+        }
+    }
+}
+
+#[derive(Copy, Clone, Default, Debug)]
+struct Modes {
+    a: Mode,
+    b: Mode,
+    c: Mode,
+}
+
+impl From<(Mode, Mode, Mode)> for Modes {
+    fn from(modes: (Mode, Mode, Mode)) -> Self {
+        Modes {
+            a: modes.0,
+            b: modes.1,
+            c: modes.2,
+        }
+    }
+}
+
+impl From<&ModedOpcode> for Modes {
+    fn from(mo: &ModedOpcode) -> Self {
+        mo.modes
+    }
+}
+
+#[derive(Copy, Clone)]
+enum Opcode {
+    Add,
+    Multiply,
+    Input,
+    Output,
+    JumpIfTrue,
+    JumpIfFalse,
+    LessThan,
+    Equals,
+    Halt,
+}
+
+impl From<&ModedOpcode> for Opcode {
+    fn from(mo: &ModedOpcode) -> Self {
+        mo.op
+    }
+}
+
+impl From<i64> for Opcode {
+    fn from(i: i64) -> Self {
+        match i {
+            1 => Opcode::Add,
+            2 => Opcode::Multiply,
+            3 => Opcode::Input,
+            4 => Opcode::Output,
+            5 => Opcode::JumpIfTrue,
+            6 => Opcode::JumpIfFalse,
+            7 => Opcode::LessThan,
+            8 => Opcode::Equals,
+            99 => Opcode::Halt,
+            _ => panic!("invalid opcode {}", i),
+        }
+    }
+}
+
+struct ModedOpcode {
+    modes: Modes,
+    op: Opcode,
+}
+
+impl From<i64> for ModedOpcode {
+    fn from(i: i64) -> Self {
+        let code = i % 100;
+        let a = i % 1000 >= 100;
+        let b = i % 10000 >= 1000;
+        let c = i > 10000;
+        let modes = (Mode::from(a), Mode::from(b), Mode::from(c)).into();
+        ModedOpcode {
+            modes: modes,
+            op: Opcode::from(code),
+        }
+    }
+}
+
+struct Computer {
+    pos: usize,
+    program: Vec<i64>,
+    modes: Modes,
+    inputs: VecDeque<i64>,
+    outputs: VecDeque<i64>,
+
+    halted: bool,
+    paused: bool,
+}
+
+impl Clone for Computer {
+    fn clone(&self) -> Self {
+        Computer::from(self.program.clone())
+    }
+}
+
+impl From<File> for Computer {
+    fn from(f: File) -> Self {
+        let f = BufReader::new(f);
+        let program: Vec<i64> = f
+            .split(b',')
+            .map(|o| {
+                let o = o.unwrap();
+                let mut o = o.iter().peekable();
+                let sign = if o.peek() == Some(&&b'-') { -1 } else { 1 };
+                o.filter(|i| **i >= b'0' && **i <= b'9')
+                    .fold(0, |s, i| ((i - b'0') as i64 + 10 * s))
+                    * sign
+            })
+            .collect();
+        program.into()
+    }
+}
+
+impl From<Vec<i64>> for Computer {
+    fn from(program: Vec<i64>) -> Self {
+        Computer {
+            pos: 0,
+            program: program,
+            modes: Default::default(),
+            inputs: VecDeque::new(),
+            outputs: VecDeque::new(),
+            halted: false,
+            paused: false,
+        }
+    }
+}
+
+impl Computer {
+    fn clone_with_modified_program(&self, u: Vec<(usize, i64)>) -> Computer {
+        let mut computer = self.clone();
+        for (pos, val) in u {
+            computer.program[pos] = val;
+        }
+        computer
+    }
+
+    fn clone_with_input(&self, input: Vec<i64>) -> Computer {
+        let mut computer = self.clone();
+        computer.inputs = input.into();
+        computer
+    }
+
+    fn run(&mut self) {
+        loop {
+            self.step();
+        }
+    }
+
+    fn run_until_output(&mut self) -> i64 {
+        loop {
+            self.step();
+            if self.outputs.len() > 0 {
+                return self.outputs.pop_front().unwrap();
+            }
+        }
+    }
+
+    fn step(&mut self) {
+        let instruction = self.program[self.pos];
+        let instruction = ModedOpcode::from(instruction);
+        self.modes = (&instruction).into();
+        let advance = match (&instruction).into() {
+            Opcode::Add => self.add(),
+            Opcode::Multiply => self.multiply(),
+            Opcode::Input => self.input(),
+            Opcode::Output => self.output(),
+            Opcode::JumpIfTrue => self.jump_if_true(),
+            Opcode::JumpIfFalse => self.jump_if_false(),
+            Opcode::LessThan => self.less_than(),
+            Opcode::Equals => self.equals(),
+            Opcode::Halt => self.halt(),
+        };
+        self.pos += advance;
+    }
+
+    fn get_a(&self) -> i64 {
+        let a = self.program[self.pos + 1];
+        match self.modes.a {
+            Mode::Position => self.program[a as usize],
+            Mode::Immediate => a,
+        }
+    }
+
+    fn set_a(&mut self, value: i64) {
+        let a = self.program[self.pos + 1];
+        match self.modes.a {
+            Mode::Position => self.program[a as usize] = value,
+            Mode::Immediate => self.program[self.pos] = value,
+        }
+    }
+
+    fn get_b(&self) -> i64 {
+        let b = self.program[self.pos + 2];
+        match self.modes.b {
+            Mode::Position => self.program[b as usize],
+            Mode::Immediate => b,
+        }
+    }
+
+    fn set_c(&mut self, value: i64) {
+        let c = self.program[self.pos + 3];
+        match self.modes.c {
+            Mode::Position => self.program[c as usize] = value,
+            Mode::Immediate => self.program[self.pos] = value,
+        }
+    }
+
+    fn add(&mut self) -> usize {
+        self.set_c(self.get_a() + self.get_b());
+        4
+    }
+
+    fn multiply(&mut self) -> usize {
+        self.set_c(self.get_a() * self.get_b());
+        4
+    }
+
+    fn input(&mut self) -> usize {
+        let value = self.inputs.pop_front().expect("no input provided");
+        self.set_a(value);
+        2
+    }
+
+    fn output(&mut self) -> usize {
+        self.outputs.push_back(self.get_a());
+        2
+    }
+
+    fn jump_if_true(&mut self) -> usize {
+        if self.get_a() > 0 {
+            self.pos = self.get_b() as usize;
+            return 0;
+        }
+        3
+    }
+
+    fn jump_if_false(&mut self) -> usize {
+        if self.get_a() == 0 {
+            self.pos = self.get_b() as usize;
+            return 0;
+        }
+        3
+    }
+
+    fn less_than(&mut self) -> usize {
+        if self.get_a() < self.get_b() {
+            self.set_c(1)
+        } else {
+            self.set_c(0)
+        }
+        4
+    }
+
+    fn equals(&mut self) -> usize {
+        if self.get_a() == self.get_b() {
+            self.set_c(1)
+        } else {
+            self.set_c(0)
+        }
+        4
+    }
+
+    fn halt(&mut self) -> usize {
+        self.halted = true;
+        0
+    }
+}
+
+fn build_args(elements: Vec<i64>, length: usize) -> Vec<Vec<i64>> {
+    let mut outs: Vec<Vec<i64>> = Vec::new();
+    if length == 1 {
+        for e in elements {
+            outs.push(vec![e]);
+        }
+        return outs;
+    }
+    for i in 0..length {
+        let current: Vec<i64> = vec![elements[i]];
+        let mut child_elements = elements.clone();
+        child_elements.remove(i);
+        for child in build_args(child_elements, length - 1) {
+            let mut current = current.clone();
+            current.append(&mut child.clone());
+            outs.push(current);
+        }
+    }
+    outs
+}
+
+fn main() -> io::Result<()> {
+    let filename = env::args().nth(1).expect("provide file as first param");
+    let computer = Computer::from(File::open(filename)?);
+
+    let orders = build_args(vec![0, 1, 2, 3, 4], 5);
+    let results: (i64, String) = orders
+        .iter()
+        .map(|order| {
+            let mut amp_a = computer.clone_with_input(vec![order[0], 0]);
+            let mut amp_b = computer.clone_with_input(vec![order[1], amp_a.run_until_output()]);
+            let mut amp_c = computer.clone_with_input(vec![order[2], amp_b.run_until_output()]);
+            let mut amp_d = computer.clone_with_input(vec![order[3], amp_c.run_until_output()]);
+            let mut amp_e = computer.clone_with_input(vec![order[4], amp_d.run_until_output()]);
+            (
+                amp_e.run_until_output(),
+                order
+                    .iter()
+                    .map(|i| i.to_string())
+                    .collect::<Vec<String>>()
+                    .join(""),
+            )
+        })
+        .fold(None, |max, (output, order)| {
+            Some(match max {
+                None => (output, order),
+                Some((output_max, order_max)) => {
+                    if output > output_max {
+                        (output, order)
+                    } else {
+                        (output_max, order_max)
+                    }
+                }
+            })
+        })
+        .unwrap();
+    println!("{:?}", results);
+
+    Ok(())
+}