Task: Data-transform-reshape (source dataset: Auto-Tables)

Given a table, predict what python pandas transformation may be needed on the given input table. Valid choices for transformation include: {"stack", "wide_to_long", "transpose", "pivot", "explode", "ffill", "subtitles"}. Note that each of these is a common Python Pandas operator. Some transformations can have parameters. Each transformation and its parameters are describe as follows.
 
- stack: collapse homogeneous cols into rows.
@param (int): stack_start_idx: zero-based starting column index of the homogeneous column-group.
@param (int): stack_end_idx: zero-based ending column index of the homogeneous column-group.
 
- wide_to_long: collapse repeating col-groups into rows.
@param (int): wide_to_long_start_idx: zero-based starting column index of the repeating col-groups.
@param (int): wide_to_long_end_idx: zero-based ending column index of the repeating col-groups.
 
- transpose: convert rows to columns and vice versa.
 
- pivot: pivot repeating row-groups into cols.
@param (int): pivot_row_frequency: frequency of repeating row-groups.
 
- ffill: fill structurally empty cells in tables.
@param (int): ffill_end_idx: zero-based ending column index of the columns to be filled.
 
- explode: convert composite cells into atomic values
@param (int): explode_column_idx: zero-based column index of the column to be exploded.
 
- subtitle: convert table subtitles into a column.
 
OUTPUT the predicted transformation name along with its parameters for the given INPUT table in a JSON, e.g., {"transformation": "stack", "stack_start_idx": 1, "stack_end_idx": 5}. If the input table needs multi-step transformations (e.g, ffill followed by stack), list JSON of each transformation sequentially in a list, e.g., [{"transformation": "ffill", "ffill_end_idx": 1}, {"transformation": "stack", "stack_start_idx": 1, "stack_end_idx": 5}]. No explanation is needed.

## Input:
| Year   | Author                  | Book                                                                                           | Award   |
|:-------|:------------------------|:-----------------------------------------------------------------------------------------------|:--------|
| 1922.0 | Hendrik Willem van Loon | The Story of Mankind                                                                           | Winner  |
|        | Charles Boardman Hawes  | The Great Quest                                                                                | Honor   |
|        | Bernard Marshall        | Cedric the Forester                                                                            | Honor   |
|        | William Bowen           | The Old Tobacco Shop: A True Account of What Befell a Little Boy in Search of Adventure        | Honor   |
|        | Padraic Colum           | The Golden Fleece and the Heroes Who Lived Before Achilles                                     | Honor   |
|        | Cornelia Meigs          | The Windy Hill                                                                                 | Honor   |
| 1923.0 | Hugh Lofting            | The Voyages of Doctor Dolittle                                                                 | Winner  |
| 1924.0 | Charles Boardman Hawes  | The Dark Frigate                                                                               | Winner  |
| 1925.0 | Charles Finger          | Tales from Silver Lands                                                                        | Winner  |
|        | Annie Carroll Moore     | Nicholas: A Manhattan Christmas Story                                                          | Honor   |
|        | Anne Parrish            | The Dream Coach                                                                                | Honor   |
|        | & Dillwyn Parrish[b]    |                                                                                                |         |
| 1926.0 | Arthur Bowie Chrisman   | Shen of the Sea                                                                                | Winner  |
|        | Padraic Colum           | The Voyagers: Being Legends and Romances of Atlantic Discovery                                 | Honor   |
| 1927.0 | Will James              | Smoky the Cow Horse                                                                            | Winner  |
| 1928.0 | Dhan Gopal Mukerji      | Gay Neck, the Story of a Pigeon                                                                | Winner  |
|        | Ella Young              | The Wonder Smith and His Son                                                                   | Honor   |
|        | Caroline Snedeker       | Downright Dencey                                                                               | Honor   |
| 1929.0 | Eric P. Kelly           | The Trumpeter of Krakow                                                                        | Winner  |
|        | John Bennett            | The Pigtail of Ah Lee Ben Loo with Seventeen Other Laughable Tales and 200 Comical Silhouettes | Honor   |
|        | Wanda Gág               | Millions of Cats                                                                               | Honor   |
|        | Grace Hallock           | The Boy Who Was                                                                                | Honor   |
|        | Cornelia Meigs          | Clearing Weather                                                                               | Honor   |
|        | Grace Moon              | Runaway Papoose                                                                                | Honor   |
|        | Elinor Whitney Field    | Tod of the Fens                                                                                | Honor   |

## Output:


source: wikipedia
label: ffill