diff --git a/2019/day7/day7.py b/2019/day7/day7.py
new file mode 100644
index 0000000..b8d6e58
--- /dev/null
+++ b/2019/day7/day7.py
@@ -0,0 +1,53 @@
+import sys
+from pathlib import Path
+
+# TODO replace PYTHONPATH hack with a proper solution, like making intcode an
+# installed module https://stackoverflow.com/a/50194143
+sys.path.append(str(Path(__file__).absolute().parent.parent / "intcode"))
+
+import itertools
+from intcode import interpret_intcode
+
+
+def main(inp):
+    mem = list(map(int, inp.readline().rstrip().split(",")))
+    max_ret = 0
+    for seq in itertools.permutations([0, 1, 2, 3, 4], 5):
+        ret = amplifiers(mem, list(seq))
+        #print(ret)
+        max_ret = max(ret[0], max_ret)
+    print(max_ret)
+
+
+def amplifiers(program, sequence):
+    ret = interpret_intcode(program[::], [sequence.pop(0), 0])
+    ret = interpret_intcode(program[::], [sequence.pop(0), ret.pop()])
+    ret = interpret_intcode(program[::], [sequence.pop(0), ret.pop()])
+    ret = interpret_intcode(program[::], [sequence.pop(0), ret.pop()])
+    ret = interpret_intcode(program[::], [sequence.pop(0), ret.pop()])
+    return ret
+
+def tests():
+    program = [3, 15, 3, 16, 1002, 16, 10, 16, 1, 16, 15, 15, 4, 15, 99, 0, 0]
+    sequence = [4, 3, 2, 1, 0]
+    res = amplifiers(program, sequence)
+    assert res == [43210]
+
+    program = [3,23,3,24,1002,24,10,24,1002,23,-1,23, 101,5,23,23,1,24,23,23,4,23,99,0,0]
+    sequence = [0,1,2,3,4]
+    res = amplifiers(program, sequence)
+    assert res == [54321]
+
+
+    program = [3,31,3,32,1002,32,10,32,1001,31,-2,31,1007,31,0,33, 1002,33,7,33,1,33,31,31,1,32,31,31,4,31,99,0,0,0]
+    sequence = [1,0,4,3,2]
+    res = amplifiers(program, sequence)
+    assert res == [65210]
+
+    print("All tests passed")
+
+if __name__ == "__main__":
+    import fileinput
+    main(fileinput.input())
+    tests()
+
diff --git a/2019/intcode/intcode.py b/2019/intcode/intcode.py
new file mode 100644
index 0000000..5c1655c
--- /dev/null
+++ b/2019/intcode/intcode.py
@@ -0,0 +1,132 @@
+#! /usr/bin/env python3
+from collections import namedtuple
+from enum import Enum
+import logging
+
+logging.basicConfig(format="%(levelname)s:%(message)s", level=logging.DEBUG)
+
+
+def get_nth_digit(n, number):
+    "Returns the nth digit of the input number"
+    return number // 10 ** n % 10
+
+
+class Operation(Enum):
+    ADDITION = 1
+    MULTIPLICATION = 2
+    INPUT = 3
+    OUTPUT = 4
+    JMP_IF_TRUE = 5
+    JMP_IF_FALSE = 6
+    LESS_THAN = 7
+    EQUALS = 8
+    TERMINATION = 99
+
+
+class Mode(Enum):
+    POSITION = 0
+    IMMEDIATE = 1
+
+
+class Instruction:
+    def __init__(self, opcode):
+        self.opcode = opcode
+        # A B C D E
+        # 0 1 1 0 3 
+        # A B C modes, DE opcode
+        self.operation = Operation(opcode % 100)
+        self.modes = [Mode(get_nth_digit(n, opcode)) for n in range(2, 5)]
+        self.handler_name = f"handle_{self.operation.name.lower()}"
+        self.handler = getattr(self, self.handler_name, self.handle_termination)
+        self.input = None
+        self.output = None
+
+    def __repr__(self):
+        return f"[{self.opcode}] Instruction({self.operation}, {self.modes})"
+
+    def handle(self, program, ip):
+        return self.handler(program, ip)
+
+    def handle_addition(self, program, ip):
+        first, second = self._get_parameters(program, ip)
+        logging.debug(f"ADD {first} {second}")
+        result = first + second
+        # the last mode should *always* be POSITION
+        program[program[ip + 3]] = result
+        ip += 4
+        return ip
+
+    def handle_multiplication(self, program, ip):
+        first, second = self._get_parameters(program, ip)
+        logging.debug(f"MUL {first} {second}")
+        result = first * second
+        # the last mode should *always* be POSITION
+        program[program[ip + 3]] = result
+        ip += 4
+        return ip
+
+    def handle_input(self, program, ip):
+        program[program[ip + 1]] = self.input
+        ip += 2
+        return ip
+
+    def handle_output(self, program, ip):
+        self.output = self._get_param(program, ip)
+        logging.debug(f"OUT {self.output}")
+        ip += 2
+        return ip
+
+    def handle_jmp_if_true(self, program, ip):
+        first, second = self._get_parameters(program, ip)
+        logging.debug(f"JMPT {first} {second}")
+        return second if first != 0 else ip + 3
+
+    def handle_jmp_if_false(self, program, ip):
+        first, second = self._get_parameters(program, ip)
+        logging.debug(f"JMPF {first} {second}")
+        return second if first == 0 else ip + 3
+
+    def handle_less_than(self, program, ip):
+        first, second = self._get_parameters(program, ip)
+        logging.debug(f"LT {first} {second}")
+        program[program[ip + 3]] = int(first < second)
+        ip += 4
+        return ip
+
+    def handle_equals(self, program, ip):
+        first, second = self._get_parameters(program, ip)
+        logging.debug(f"EQ {first} {second}")
+        program[program[ip + 3]] = int(first == second)
+        ip += 4
+        return ip
+
+    def handle_termination(self, program, ip):
+        logging.debug("HALT")
+        return ip
+
+    def _get_param(self, program, ip, i=0):
+        return (
+            program[ip + i + 1]
+            if self.modes[i] is Mode.IMMEDIATE
+            else program[program[ip + i + 1]]
+        )
+
+    def _get_parameters(self, program, ip):
+        first = self._get_param(program, ip, 0)
+        second = self._get_param(program, ip, 1)
+        return first, second
+
+
+def interpret_intcode(program, stdin=[]):
+    ip = 0
+    out = []
+    while program[ip] != 99:
+        opcode = program[ip]
+        instruction = Instruction(opcode)
+        if instruction.operation == Operation.INPUT:
+            instruction.input=stdin.pop(0)
+        ip = instruction.handle(program, ip)
+        if instruction.output is not None:
+            out.append(instruction.output)
+    return out
+
diff --git a/2019/intcode/tests.py b/2019/intcode/tests.py
new file mode 100644
index 0000000..d12ff07
--- /dev/null
+++ b/2019/intcode/tests.py
@@ -0,0 +1,83 @@
+# Run with pytest
+import logging
+from intcode import *
+
+
+def run_test(program, expected_mem=None, stdin=[], expected_out=None):
+    mem = program[::]
+    out = interpret_intcode(mem, stdin=stdin)
+
+    if expected_mem is not None:
+        assert expected_mem == mem
+    if expected_out is not None:
+        assert expected_out == out
+
+
+def test_day2():
+    tests = [
+        [[1,0,0,0,99], [2,0,0,0,99]],  # ADD 1 + 1 to location 0
+        [[2,3,0,3,99], [2,3,0,6,99]],  # MUL 2 * 3 to location 3
+        [[2,4,4,5,99,0], [2,4,4,5,99,9801]],  # MUL 99 * 99 to location 5 (9801)
+        [[1,1,1,4,99,5,6,0,99], [30,1,1,4,2,5,6,0,99]],
+    ]
+    for program, expected in tests:
+        run_test(program, expected)
+
+
+def test_day5_basic():
+    # Using position mode, consider whether the input is equal to 8; output 1
+    # (if it is) or 0 (if it is not).
+    prog = [3,9,8,9,10,9,4,9,99,-1,8]
+    run_test(prog, stdin=[0], expected_out=[0])
+    run_test(prog, stdin=[8], expected_out=[1])
+
+    # Using position mode, consider whether the input is less than 8; output 1
+    # (if it is) or 0 (if it is not).
+    prog = [3,9,7,9,10,9,4,9,99,-1,8]
+    run_test(prog, stdin=[7], expected_out=[1])
+    run_test(prog, stdin=[9], expected_out=[0])
+
+    # Using immediate mode, consider whether the input is equal to 8; output 1
+    # (if it is) or 0 (if it is not).
+    prog = [3,3,1108,-1,8,3,4,3,99]
+    run_test(prog, stdin=[8], expected_out=[1])
+    run_test(prog, stdin=[9], expected_out=[0])
+
+    # Using immediate mode, consider whether the input is less than 8; output 1
+    # (if it is) or 0 (if it is not).
+    prog = [3,3,1107,-1,8,3,4,3,99]
+    run_test(prog, stdin=[7], expected_out=[1])
+    run_test(prog, stdin=[9], expected_out=[0])
+
+    # Here are some jump tests that take an input, then output 0 if the input
+    # was zero or 1 if the input was non-zero:
+    prog = [3,12,6,12,15,1,13,14,13,4,13,99,-1,0,1,9]  # using position mode
+    run_test(prog, stdin=[0], expected_out=[0])
+    run_test(prog, stdin=[4], expected_out=[1])
+
+    prog = [3,12,6,12,15,1,13,14,13,4,13,99,-1,0,1,9]  # using immediate mode
+    run_test(prog, stdin=[0], expected_out=[0])
+    run_test(prog, stdin=[4], expected_out=[1])
+
+
+def test_day5_larger():
+    """
+    The above example program uses an input instruction to ask for a single
+    number. The program will then output 999 if the input value is below 8,
+    output 1000 if the input value is equal to 8, or output 1001 if the input
+    value is greater than 8.
+    """
+    prog = [3,21,1008,21,8,20,1005,20,22,107,8,21,20,1006,20,31,
+            1106,0,36,98,0,0,1002,21,125,20,4,20,1105,1,46,104,
+            999,1105,1,46,1101,1000,1,20,4,20,1105,1,46,98,99]
+    run_test(prog, stdin=[7], expected_out=[999])
+    run_test(prog, stdin=[8], expected_out=[1000])
+    run_test(prog, stdin=[9], expected_out=[1001])
+
+
+def test():
+    # factorial test
+    fac = [3,29,1007,29,2,28,1005,28,24,2,27,29,27,1001,29,-1,29,1101,0,0,28,1006,28,2,4,27,99,1,0,0]
+    res = interpret_intcode(fac, [4]) 
+    assert res == [24], f"Expected 24 but got {res}"
+