# Day 4
```elixir
Mix.install([:kino])
```
## Read Input
```elixir
file_input = Kino.Input.file("Please Select Input File")
```
```elixir
file_info = Kino.Input.read(file_input)
file_path = Kino.Input.file_path(file_info.file_ref)
contents = File.read!(file_path)
```
```elixir
{grid, start_points} = contents
|> String.split("\n")
|> Enum.with_index()
|> Enum.reduce({%{}, []}, fn({line, y}, {grid, start_points}) ->
line
|> String.graphemes()
|> Enum.with_index()
|> Enum.reduce({grid, start_points}, fn({char, x}, {grid, start_points}) ->
cond do
char == "X" ->
{Map.put(grid, {x, y}, char), [{x, y} | start_points]}
Enum.member?(["M", "A", "S"], char) ->
{Map.put(grid, {x, y}, char), start_points}
true ->
{grid, start_points}
end
end)
end)
```
```elixir
defmodule GraphTraversal do
@search_diffs [{1, 0}, {1, 1}, {0, 1}, {-1, 1}, {-1, 0}, {-1, -1}, {0, -1}, {1, -1}]
def find_sequence(start_x, start_y, grid, sequence) do
@search_diffs
|> Enum.reduce(0, fn({dx, dy}, found) ->
find_sequence(start_x, start_y, grid, sequence, dx, dy, found)
end)
end
def find_sequence(_x, _y, _grid, [], _dx, _dy, found),
do: found + 1
def find_sequence(x, y, grid, [current | rest], dx, dy, found) do
case Map.get(grid, {x, y}) do
^current -> find_sequence(x + dx, y + dy, grid, rest, dx, dy, found)
_ -> found
end
end
end
```
```elixir
GraphTraversal.find_sequence(9, 9, grid, ["X", "M", "A", "S"])
```
## Part 1
```elixir
start_points
|> Enum.reduce(0, fn({x, y}, found) ->
found + GraphTraversal.find_sequence(x, y, grid, ["X", "M", "A", "S"])
end)
```
## Part 2
```elixir
```
