Implement Text Layout and Query Parsing

Problem Statement

Airbnb listing titles and descriptions must be rendered dynamically across various web and mobile layouts. You are tasked with implementing a function that extracts layout parameters from a URL request and formats the display text into wrapped lines.

Your task is to write a function format_query_text(url: str) -> list[str] that performs two operations:

1. URL Query Parsing:

   • Extract the query parameters following the ? character in the url.
   • Key-value pairs are separated by &, and keys are separated from values by =. If a key has no value or = is omitted, treat its value as an empty string.
   • Decode spaces in values: replace occurrences of + and %20 with a single space ' '.
   • Extract text (the text string to wrap) and width (an integer maximum line width). If width is missing or not a valid positive integer, default to 20. If text is missing or empty, return an empty list [].

2. Text Layout & Wrapping:

   • Split text into words by whitespace.
   • Pack words greedily into lines such that each line contains as many words as possible without its total character count (including single spaces between words) exceeding width.
   • Any trailing punctuation attached to a word (e.g., "cabin," or "view!") is treated as part of that word.
   • Orphan Prevention: If the resulting layout produces more than one line and the final line contains only a single word, rebalance the last two lines if possible. Specifically, move the last word from the second-to-last line to the beginning of the final line, provided that:
     • The second-to-last line had at least 2 words prior to the move, and
     • The new final line does not exceed width.
     • If moving the word would exceed width, leave the layout as-is.

Interface

def format_query_text(url: str) -> list[str]:
    pass

Input & Output

• Input: url: str - a URL string possibly containing query parameters.
• Output: list[str] - a list of lines representing the wrapped text.

Constraints

• 1 <= len(url) <= 1000
• 5 <= width <= 100
• You may assume every individual word has a length less than or equal to width.
• No built-in URL parsing libraries (such as urllib.parse) should be used; implement parsing manually.

Examples

Example 1

url = "https://airbnb.com/search?text=Cozy+cabin+in+the+woods&width=10"
output = format_query_text(url)
# Output: ["Cozy cabin", "in", "the woods"]

Explanation:

1. Parameters extracted: text = "Cozy cabin in the woods", width = 10.
2. Greedy wrapping gives: ["Cozy cabin", "in the", "woods"].
3. The last line has only 1 word ("woods"). The preceding line has 2 words ("in the"). Moving "the" down creates "the woods" (length 9 <= 10), leaving "in" on the second-to-last line.

Example 2

url = "https://airbnb.com/rooms?text=Quiet%20loft&width=20"
output = format_query_text(url)
# Output: ["Quiet loft"]

Explanation:

1. Parameters: text = "Quiet loft", width = 20.
2. Both words fit within width 20 on a single line.