adventofcode/2019/day05/problem

Advent of Code

--- Day 5: Sunny with a Chance of Asteroids ---

   You're starting to sweat as the ship makes its way toward Mercury. The Elves
   suggest that you get the air conditioner working by upgrading your ship
   computer to support the Thermal Environment Supervision Terminal.

   The Thermal Environment Supervision Terminal (TEST) starts by running a
   diagnostic program (your puzzle input). The TEST diagnostic program will run
   on your existing Intcode computer after a few modifications:

   First, you'll need to add two new instructions:

     • Opcode 3 takes a single integer as input and saves it to the position
     given by its only parameter. For example, the instruction 3,50 would take
     an input value and store it at address 50. • Opcode 4 outputs the value of
     its only parameter. For example, the instruction 4,50 would output the
     value at address 50.

   Programs that use these instructions will come with documentation that
   explains what should be connected to the input and output. The program
   3,0,4,0,99 outputs whatever it gets as input, then halts.

   Second, you'll need to add support for parameter modes:

   Each parameter of an instruction is handled based on its parameter mode.
   Right now, your ship computer already understands parameter mode 0, position
   mode, which causes the parameter to be interpreted as a position - if the
   parameter is 50, its value is the value stored at address 50 in memory.
   Until now, all parameters have been in position mode.

   Now, your ship computer will also need to handle parameters in mode 1,
   immediate mode. In immediate mode, a parameter is interpreted as a value -
   if the parameter is 50, its value is simply 50.

   Parameter modes are stored in the same value as the instruction's opcode.
   The opcode is a two-digit number based only on the ones and tens digit of
   the value, that is, the opcode is the rightmost two digits of the first
   value in an instruction. Parameter modes are single digits, one per
   parameter, read right-to-left from the opcode: the first parameter's mode is
   in the hundreds digit, the second parameter's mode is in the thousands
   digit, the third parameter's mode is in the ten-thousands digit, and so on.
   Any missing modes are 0.

   For example, consider the program 1002,4,3,4,33.

   The first instruction, 1002,4,3,4, is a multiply instruction - the rightmost
   two digits of the first value, 02, indicate opcode 2, multiplication. Then,
   going right to left, the parameter modes are 0 (hundreds digit), 1
   (thousands digit), and 0 (ten-thousands digit, not present and therefore
   zero):

 ABCDE 1002

 DE - two-digit opcode,      02 == opcode 2 C - mode of 1st parameter,  0 ==
 position mode B - mode of 2nd parameter,  1 == immediate mode A - mode of 3rd
 parameter,  0 == position mode, omitted due to being a leading zero

   This instruction multiplies its first two parameters. The first parameter, 4
   in position mode, works like it did before - its value is the value stored
   at address 4 (33). The second parameter, 3 in immediate mode, simply has
   value 3. The result of this operation, 33 * 3 = 99, is written according to
   the third parameter, 4 in position mode, which also works like it did before
   - 99 is written to address 4.

   Parameters that an instruction writes to will never be in immediate mode.

   Finally, some notes:

     • It is important to remember that the instruction pointer should increase
     by the number of values in the instruction after the instruction finishes.
     Because of the new instructions, this amount is no longer always 4.
     • Integers can be negative: 1101,100,-1,4,0 is a valid program (find 100 +
     -1, store the result in position 4).

   The TEST diagnostic program will start by requesting from the user the ID of
   the system to test by running an input instruction - provide it 1, the ID
   for the ship's air conditioner unit.

   It will then perform a series of diagnostic tests confirming that various
   parts of the Intcode computer, like parameter modes, function correctly. For
   each test, it will run an output instruction indicating how far the result
   of the test was from the expected value, where 0 means the test was
   successful. Non-zero outputs mean that a function is not working correctly;
   check the instructions that were run before the output instruction to see
   which one failed.

   Finally, the program will output a diagnostic code and immediately halt.
   This final output isn't an error; an output followed immediately by a halt
   means the program finished. If all outputs were zero except the diagnostic
   code, the diagnostic program ran successfully.

   After providing 1 to the only input instruction and passing all the tests,
   what diagnostic code does the program produce?

   Your puzzle answer was 16489636.

--- Part Two ---

   The air conditioner comes online! Its cold air feels good for a while, but
   then the TEST alarms start to go off. Since the air conditioner can't vent
   its heat anywhere but back into the spacecraft, it's actually making the air
   inside the ship warmer.

   Instead, you'll need to use the TEST to extend the thermal radiators.
   Fortunately, the diagnostic program (your puzzle input) is already equipped
   for this. Unfortunately, your Intcode computer is not.

   Your computer is only missing a few opcodes:

     • Opcode 5 is jump-if-true: if the first parameter is non-zero, it sets
     the instruction pointer to the value from the second parameter. Otherwise,
     it does nothing. • Opcode 6 is jump-if-false: if the first parameter is
     zero, it sets the instruction pointer to the value from the second
     parameter. Otherwise, it does nothing. • Opcode 7 is less than: if the
     first parameter is less than the second parameter, it stores 1 in the
     position given by the third parameter. Otherwise, it stores 0. • Opcode 8
     is equals: if the first parameter is equal to the second parameter, it
     stores 1 in the position given by the third parameter. Otherwise, it
     stores 0.

   Like all instructions, these instructions need to support parameter modes as
   described above.

   Normally, after an instruction is finished, the instruction pointer
   increases by the number of values in that instruction. However, if the
   instruction modifies the instruction pointer, that value is used and the
   instruction pointer is not automatically increased.

   For example, here are several programs that take one input, compare it to
   the value 8, and then produce one output:

     • 3,9,8,9,10,9,4,9,99,-1,8 - Using position mode, consider whether the
     input is equal to 8; output 1 (if it is) or 0 (if it is not).
     • 3,9,7,9,10,9,4,9,99,-1,8 - Using position mode, consider whether the
     input is less than 8; output 1 (if it is) or 0 (if it is not).
     • 3,3,1108,-1,8,3,4,3,99 - Using immediate mode, consider whether the
     input is equal to 8; output 1 (if it is) or 0 (if it is not).
     • 3,3,1107,-1,8,3,4,3,99 - Using immediate mode, consider whether the
     input is less than 8; output 1 (if it is) or 0 (if it is not).

   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:

     • 3,12,6,12,15,1,13,14,13,4,13,99,-1,0,1,9 (using position mode)
     • 3,3,1105,-1,9,1101,0,0,12,4,12,99,1 (using immediate mode)

   Here's a larger example:

 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

   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.

   This time, when the TEST diagnostic program runs its input instruction to
   get the ID of the system to test, provide it 5, the ID for the ship's
   thermal radiator controller. This diagnostic test suite only outputs one
   number, the diagnostic code.

   What is the diagnostic code for system ID 5?

   Your puzzle answer was 9386583.

   Both parts of this puzzle are complete! They provide two gold stars: **

   At this point, you should return to your Advent calendar and try another
   puzzle.

   If you still want to see it, you can get your puzzle input.

References

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   https://adventofcode.com/2019/about . https://adventofcode.com/2019/events .
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   https://adventofcode.com/2019/support . https://adventofcode.com/2019 .
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   https://adventofcode.com/2019/leaderboard .
   https://adventofcode.com/2019/stats . https://adventofcode.com/2019/sponsors
   https://adventofcode.com/2019/day/2 .
   https://en.wikipedia.org/wiki/Spacecraft_thermal_control .
   https://adventofcode.com/2019 . https://adventofcode.com/2019/day/5/input .