Solution.java

class Solution {
    public List<String> fullJustify(String[] words, int maxWidth) {
        List<String> ans = new ArrayList<>();
        for (int i = 0, n = words.length; i < n;) {
            List<String> t = new ArrayList<>();
            t.add(words[i]);
            int cnt = words[i].length();
            ++i;
            while (i < n && cnt + 1 + words[i].length() <= maxWidth) {
                cnt += 1 + words[i].length();
                t.add(words[i++]);
            }
            if (i == n || t.size() == 1) {
                String left = String.join(" ", t);
                String right = " ".repeat(maxWidth - left.length());
                ans.add(left + right);
                continue;
            }
            int spaceWidth = maxWidth - (cnt - t.size() + 1);
            int w = spaceWidth / (t.size() - 1);
            int m = spaceWidth % (t.size() - 1);
            StringBuilder row = new StringBuilder();
            for (int j = 0; j < t.size() - 1; ++j) {
                row.append(t.get(j));
                row.append(" ".repeat(w + (j < m ? 1 : 0)));
            }
            row.append(t.get(t.size() - 1));
            ans.add(row.toString());
        }
        return ans;
    }
}