feat(string): text justification

Author: BrianLusina

pystrings/text_justification/README.md

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+# Text Justification
+
+Given an array of strings words and a width maxWidth, format the text such that each line has exactly maxWidth
+characters 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 maxWidth characters.
+
+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.
+
+Note:
+
+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 maxWidth.
+The input array words contains at least one word.
+
+```text
+Example 1:
+
+Input: words = ["This", "is", "an", "example", "of", "text", "justification."], maxWidth = 16
+Output:
+[
+    "This    is    an",
+    "example  of text",
+    "justification.  "
+]
+```
+
+```text
+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.
+```
+
+```text
+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                  "
+]
+```
+
+## Related Topics
+
+- Array
+- String
+- Simulation

pystrings/text_justification/__init__.py

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+from typing import List
+
+
+def full_justify(words: List[str], max_width: int) -> List[str]:
+    """
+    How does it work? This uses a round-robin. The following line implements the round-robin logic:
+    for i in range(maxWidth - num_of_letters):
+        cur[i%(len(cur)-1 or 1)] += ' '
+
+    What does this line do? Once you determine that there are only k words that can fit on a given line, you know what
+    the total length of those words is num_of_letters. Then the rest are spaces, and there are
+    (max_width - num_of_letters) of spaces. The "or 1" part is for dealing with the edge case len(cur) == 1.
+
+    Args:
+        words (list): words to fully justify
+        max_width (int): width of each line
+    Returns:
+         list: list of justified words
+    """
+    res, cur, num_of_letters = [], [], 0
+    for w in words:
+        if num_of_letters + len(w) + len(cur) > max_width:
+            for i in range(max_width - num_of_letters):
+                cur[i % (len(cur) - 1 or 1)] += ' '
+            res.append(''.join(cur))
+            cur, num_of_letters = [], 0
+        cur += [w]
+        num_of_letters += len(w)
+    return res + [' '.join(cur).ljust(max_width)]

pystrings/text_justification/test_text_justification.py

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+import unittest
+from . import full_justify
+
+
+class FullJustifyTestCase(unittest.TestCase):
+    def test_1(self):
+        """words = ["This", "is", "an", "example", "of", "text", "justification."], maxWidth = 16"""
+        words = ["This", "is", "an", "example", "of", "text", "justification."]
+        max_width = 16
+        expected = [
+            "This    is    an",
+            "example  of text",
+            "justification.  "
+        ]
+        actual = full_justify(words, max_width)
+        self.assertListEqual(expected, actual)
+
+    def test_2(self):
+        """words = ["What","must","be","acknowledgment","shall","be"], maxWidth = 16"""
+        words = ["What", "must", "be", "acknowledgment", "shall", "be"]
+        max_width = 16
+        expected = [
+            "What   must   be",
+            "acknowledgment  ",
+            "shall be        "
+        ]
+        actual = full_justify(words, max_width)
+        self.assertListEqual(expected, actual)
+
+    def test_3(self):
+        """words = ["Science","is","what","we","understand","well","enough","to","explain","to","a","computer.","Art",
+        "is","everything","else","we","do"], maxWidth = 20"""
+        words = ["Science", "is", "what", "we", "understand", "well", "enough", "to", "explain", "to", "a", "computer.",
+                 "Art", "is", "everything", "else", "we", "do"]
+        max_width = 20
+        expected = [
+            "Science  is  what we",
+            "understand      well",
+            "enough to explain to",
+            "a  computer.  Art is",
+            "everything  else  we",
+            "do                  "
+        ]
+        actual = full_justify(words, max_width)
+        self.assertListEqual(expected, actual)
+
+
+if __name__ == '__main__':
+    unittest.main()