Day 5

Part 1

I think for preprocessing the text, I’m going to start off with python.

```{r}
library(reticulate)
```

```{python}
with open("2022-12-5_assets/input.txt", "r") as data:
  lines = data.readlines()
```

Setting up the initial state

```{python}
initial_state = [x.replace("\n", "") 
                  for x in lines 
                    if "move" not in x and len(x) > 1]
initial_state
```

['[N]     [C]                 [Q]    ', '[W]     [J] [L]             [J] [V]', '[F]     [N] [D]     [L]     [S] [W]', '[R] [S] [F] [G]     [R]     [V] [Z]', '[Z] [G] [Q] [C]     [W] [C] [F] [G]', '[S] [Q] [V] [P] [S] [F] [D] [R] [S]', '[M] [P] [R] [Z] [P] [D] [N] [N] [M]', '[D] [W] [W] [F] [T] [H] [Z] [W] [R]', ' 1   2   3   4   5   6   7   8   9 ']

There’s not a fixed delimiter between every column. Each column is 3 characters wide, with a space in between.

```{python}
[len(x) for x in initial_state]
```

[35, 35, 35, 35, 35, 35, 35, 35, 35]

```{python}
def three_split(x):
  out = []
  start = 0
  done = False
  while not done:
    end = start + 3
    item = x[start:end].strip()
    out.append(item)
    start = end + 1
    if start > len(x):
      done = True
  return(out)
```

```{python}
state_rows = [three_split(x) for x in initial_state]
state_rows
```

[['[N]', '', '[C]', '', '', '', '', '[Q]', ''], ['[W]', '', '[J]', '[L]', '', '', '', '[J]', '[V]'], ['[F]', '', '[N]', '[D]', '', '[L]', '', '[S]', '[W]'], ['[R]', '[S]', '[F]', '[G]', '', '[R]', '', '[V]', '[Z]'], ['[Z]', '[G]', '[Q]', '[C]', '', '[W]', '[C]', '[F]', '[G]'], ['[S]', '[Q]', '[V]', '[P]', '[S]', '[F]', '[D]', '[R]', '[S]'], ['[M]', '[P]', '[R]', '[Z]', '[P]', '[D]', '[N]', '[N]', '[M]'], ['[D]', '[W]', '[W]', '[F]', '[T]', '[H]', '[Z]', '[W]', '[R]'], ['1', '2', '3', '4', '5', '6', '7', '8', '9']]

I had a big hang up here, because I created the list of empty lists with [[]] * 9, which copies the empty list, so when I appended a value to columns[0], it appended that value to all columns.

```{python}
columns = [[] for _ in range(len(state_rows[0]))]
for ridx, row in enumerate(state_rows):
  for cidx, col in enumerate(state_rows[ridx]):
    if len(col) > 0 :
      columns[cidx].append(col)
    
print(columns)
```

[['[N]', '[W]', '[F]', '[R]', '[Z]', '[S]', '[M]', '[D]', '1'], ['[S]', '[G]', '[Q]', '[P]', '[W]', '2'], ['[C]', '[J]', '[N]', '[F]', '[Q]', '[V]', '[R]', '[W]', '3'], ['[L]', '[D]', '[G]', '[C]', '[P]', '[Z]', '[F]', '4'], ['[S]', '[P]', '[T]', '5'], ['[L]', '[R]', '[W]', '[F]', '[D]', '[H]', '6'], ['[C]', '[D]', '[N]', '[Z]', '7'], ['[Q]', '[J]', '[S]', '[V]', '[F]', '[R]', '[N]', '[W]', '8'], ['[V]', '[W]', '[Z]', '[G]', '[S]', '[M]', '[R]', '9']]

Setting up the move function

```{python}
move_instructions = [x.strip() for x in lines if "move" in x]
```

```{python}
import re
move_list = [re.findall(r'\d+', line) 
              for line in move_instructions]
move_int = [[int(x[0]), int(x[1])-1, int(x[2])-1] 
              for x in move_list]
```

```{python}
def move_fun(m):
  n = m[0]
  fro = move[1]
  to = move[2]
  for i in range(n):
    columns[to].insert(0, columns[fro].pop(0))
```

```{python}
for move in move_int:
  move_fun(move)
```

```{python}
"".join([x[0].replace("[", "").replace("]", "") for x in columns])
```

'FWNSHLDNZ'

Part 2

reset initial state

```{python}
columns = [[] for _ in range(len(state_rows[0]))]
for ridx, row in enumerate(state_rows):
  for cidx, col in enumerate(state_rows[ridx]):
    if len(col) > 0 :
      columns[cidx].append(col)
```

```{python}
def move_fun9001(m):
  n = m[0]
  fro = move[1]
  to = move[2]
  columns[to] = columns[fro][0:n] + columns[to]
  columns[fro] = columns[fro][n:]
```

```{python}
for move in move_int:
  move_fun9001(move)
```

```{python}
"".join([x[0].replace("[", "").replace("]", "") for x in columns])
```

'RNRGDNFQG'