## \-\-- Day 6: Probably a Fire Hazard \-\--

Because your neighbors keep defeating you in the holiday house
decorating contest year after year, you\'ve decided to deploy one
million lights in a [1000x1000
grid]{title="Hey, be glad I'm not asking for the resistance between two points!"}.

Furthermore, because you\'ve been especially nice this year, Santa has
mailed you instructions on how to display the ideal lighting
configuration.

Lights in your grid are numbered from 0 to 999 in each direction; the
lights at each corner are at `0,0`, `0,999`, `999,999`, and `999,0`. The
instructions include whether to `turn on`, `turn off`, or `toggle`
various inclusive ranges given as coordinate pairs. Each coordinate pair
represents opposite corners of a rectangle, inclusive; a coordinate pair
like `0,0 through 2,2` therefore refers to 9 lights in a 3x3 square. The
lights all start turned off.

To defeat your neighbors this year, all you have to do is set up your
lights by doing the instructions Santa sent you in order.

For example:

-   `turn on 0,0 through 999,999` would turn on (or leave on) every
    light.
-   `toggle 0,0 through 999,0` would toggle the first line of 1000
    lights, turning off the ones that were on, and turning on the ones
    that were off.
-   `turn off 499,499 through 500,500` would turn off (or leave off) the
    middle four lights.

After following the instructions, *how many lights are lit*?

Your puzzle answer was `377891`.

## \-\-- Part Two \-\-- {#part2}

You just finish implementing your winning light pattern when you realize
you mistranslated Santa\'s message from Ancient Nordic Elvish.

The light grid you bought actually has individual brightness controls;
each light can have a brightness of zero or more. The lights all start
at zero.

The phrase `turn on` actually means that you should increase the
brightness of those lights by `1`.

The phrase `turn off` actually means that you should decrease the
brightness of those lights by `1`, to a minimum of zero.

The phrase `toggle` actually means that you should increase the
brightness of those lights by `2`.

What is the *total brightness* of all lights combined after following
Santa\'s instructions?

For example:

-   `turn on 0,0 through 0,0` would increase the total brightness by
    `1`.
-   `toggle 0,0 through 999,999` would increase the total brightness by
    `2000000`.

Your puzzle answer was `14110788`.

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

At this point, you should [return to your Advent calendar](/2015) and
try another puzzle.

If you still want to see it, you can [get your puzzle
input](6/input).