
public static String mostCommonWord(String paragraph, String[] banned) {
paragraph += ".";
Set<String> banset = new HashSet();
for (String word: banned) banset.add(word);
Map<String, Integer> count = new HashMap();
String ans = "";
int ansfreq = 0;
StringBuilder word = new StringBuilder();
for (char c: paragraph.toCharArray()) {
if (Character.isLetter(c)) {
word.append(Character.toLowerCase(c));
} else if (word.length() > 0) {
String finalword = word.toString();
if (!banset.contains(finalword)) {
count.put(finalword, count.getOrDefault(finalword, 0) + 1);
if (count.get(finalword) > ansfreq) {
ans = finalword;
ansfreq = count.get(finalword);
}
}
word = new StringBuilder();
}
}
return ans;
}