Published: Sep 23, 2022
Since this problem asks to create a fully justified result, actual simulation should be done. When and how to add spaces in-between or right end are the point we should consider.
Given an array of strings
wordsand a width
maxWidth, format the text such that each line has exactly
maxWidthcharacters and is fully (left and right) justified. You should pack your words in a greedy approach; that is, pack as many words as you can in each line. Pad extra spaces ‘ ‘ when necessary so that each line has exactly
Extra spaces between words should be distributed as evenly as possible. If the number of spaces on a line does not divide evenly between words, the empty slots on the left will be assigned more spaces than the slots on the right.
For the last line of text, it should be left-justified, and no extra space is inserted between words.
- A word is defined as a character sequence consisting of non-space characters only.
- Each word’s length is guaranteed to be greater than 0 and not exceed
- The input array
wordscontains at least one word.
1 <= words.length <= 300
1 <= words[i].length <= 20
words[i]consists of only English letters and symbols.
1 <= maxWidth <= 100
words[i].length <= maxWidth
Example 1 Input: words = ["This", "is", "an", "example", "of", "text", "justification."], maxWidth = 16 Output: [ "This is an", "example of text", "justification. " ]
Example 2 Input: words = ["What","must","be","acknowledgment","shall","be"], maxWidth = 16 Output: [ "What must be", "acknowledgment ", "shall be " ] Explanation: Note that the last line is "shall be " instead of "shall be", because the last line must be left-justified instead of fully-justified. Note that the second line is also left-justified because it contains only one word.
Example 3 Input: words = ["Science","is","what","we","understand","well","enough","to","explain","to","a","computer.","Art","is","everything","else","we","do"], maxWidth = 20 Output: [ "Science is what we", "understand well", "enough to explain to", "a computer. Art is", "everything else we", "do " ]
The solution here consists of two steps. For the first step, it creates words list for each lines. The second step calculates and adds spaces between words or right end if it is the last line. The two step approach would be easier to reach to the answer.
class TextJustification: def fullJustify(self, words: List[str], maxWidth: int) -> List[str]: line, lines, cur = , , 0 for word in words: if cur + len(word) + len(line) <= maxWidth: line.append(word) cur += len(word) else: lines.append(line) line = [word] cur = len(word) lines.append(line) for i in range(len(lines) - 1): ws = lines[i] spaces = maxWidth - sum([len(w) for w in ws]) gaps = max(1, len(ws) - 1) cnt, rem = divmod(spaces, gaps) for j in range(gaps): ws[j] += ' ' * cnt + (' ' if j < rem else '') lines[i] = ''.join(ws) lines[-1] = ' '.join(lines[-1]).ljust(maxWidth) return lines
O(m + n)– m: number of words, n: number of lines