Maximum Font To Fit A Sentence In A Screen - Leetcode Solution

Problem statement:

You are given a sentence consisting of words separated by spaces. You need to display this sentence on a screen of minimum width and height. Each word can be displayed using any font size and any font family, but each word must fit within the screen.

Write a function that returns the maximum font size that can be used to display the sentence on the screen.

Solution:

The problem can be solved using binary search on the range of font sizes. We need to find the largest font size such that all the words in the sentence fit within the screen.

We can define a function that takes the font size as input and returns the number of lines required to fit the sentence within the screen. This function can be defined as follows:

def num_lines(font_size, sentence, screen_width, screen_height):
    # Initialize the line width and height to be zero
    line_width = 0
    line_height = 0
    
    # Iterate over each word in the sentence
    for word in sentence.split():
        # Get the width and height of the word at the current font size
        word_width, word_height = get_word_size(word, font_size)
        
        # If adding the word to the current line will exceed the screen width,
        # move to the next line
        if line_width + word_width > screen_width:
            line_width = word_width
            line_height += word_height
        else:
            line_width += word_width
            
    # Calculate the total number of lines required
    num_lines = (line_height + word_height - 1) // word_height
    
    # Return the number of lines required
    return num_lines

The get_word_size function can be defined using any font rendering library such as Pillow or pygame.

Once we have defined the num_lines function, we can use binary search to find the maximum font size that can be used to fit the sentence within the screen. The binary search can be implemented as follows:

def max_font_size(sentence, screen_width, screen_height):
    # Set the lower bound and upper bound of the font size range
    lo = 1
    hi = 1000
    
    # Iterate until the lower bound is greater than the upper bound
    while lo <= hi:
        # Calculate the mid-point of the font size range
        mid = (lo + hi) // 2
        
        # Calculate the number of lines required for the current font size
        lines = num_lines(mid, sentence, screen_width, screen_height)
        
        # If the number of lines required is greater than the screen height,
        # move the upper bound of the font size range down
        if lines > screen_height:
            hi = mid - 1
        # If the number of lines required is less than or equal to the screen height,
        # move the lower bound of the font size range up
        else:
            lo = mid + 1
            
    # Return the font size that is one less than the lower bound of the font size range
    return lo - 1

The max_font_size function takes the sentence, screen width, and screen height as inputs and returns the maximum font size that can be used to fit the sentence within the screen. The function uses binary search to find the maximum font size that is less than or equal to the screen height.

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