Wrap text to a label width
A shipping label printer takes a fixed number of characters per line, and a description has to be broken across lines without splitting words.
- Fill each line greedily: keep adding words while they still fit.
- Words are separated by whitespace and joined back with a single space.
- A word longer than the whole width goes on a line of its own, unbroken.
- A width of zero or less, or text with no words, gives an empty list.
wordWrap(text: string, width: int) → list<string>
Java needs a compiler and Drill does not host one yet, so this page is the reference rather than an exercise: the problem, worked examples, and the solution in full. To type it out, the same problem runs in Python.
Where you start
List<String> wordWrap(String text, int width) {
}Worked examples
| Call | Result |
|---|---|
wordWrap("the quick brown fox", 10) | Main.<String>ls("the quick", "brown fox") |
wordWrap("a bb ccc", 3) | Main.<String>ls("a", "bb", "ccc") |
wordWrap("supercalifragilistic is long", 5) | Main.<String>ls("supercalifragilistic", "is", "long") |
wordWrap("one two", 20) | Main.<String>ls("one two") |
Hint
Track the current line as a string. Before adding a word, check whether the line plus a space plus the word still fits.
Reference solution in Java
List<String> wordWrap(String text, int width) {
List<String> lines = new ArrayList<>();
if (width <= 0) return lines;
StringBuilder line = new StringBuilder();
for (String w : text.trim().split("\\s+")) {
if (w.isEmpty()) continue;
if (line.length() == 0) line.append(w);
else if (line.length() + 1 + w.length() <= width) line.append(' ').append(w);
else { lines.add(line.toString()); line = new StringBuilder(w); }
}
if (line.length() > 0) lines.add(line.toString());
return lines;
}