力扣AC：最常见的单词 - java集合

题目链接

最常见的单词

题目描述

实现代码

个人代码，未AC，因为在力扣的编译器中没法使用StringTokenizer：

class Solution {
    public String mostCommonWord(String paragraph, String[] banned) {
        Map<String, Integer> map = new HashMap<>(paragraph.length());
        StringTokenizer tokenizer = new StringTokenizer(paragraph, " ");
        Set<String> container = new HashSet<>();
        for(String s : banned) {
            container.add(s);
        }
        int max = 0;
        String result = null;
        while (tokenizer.hasMoreTokens()) {
            String token = tokenizer.nextToken().replaceAll("[^a-zA-Z]", "").toLowerCase();
            if(container.contains(token)){
                continue;
            }
            Integer count = map.get(token);
            Integer newCount = (count == null ? 1 : count+1);
            map.put(token, newCount);
            if(max < newCount) {
                max = newCount;
                result = token;
            }
        }
        return result;
    }
}

官方实现代码：

class Solution {
    public String mostCommonWord(String paragraph, String[] banned) {
        Set<String> bannedSet = new HashSet<String>();
        for (String word : banned) {
            bannedSet.add(word);
        }
        int maxFrequency = 0;
        Map<String, Integer> frequencies = new HashMap<String, Integer>();
        StringBuffer sb = new StringBuffer();
        int length = paragraph.length();
        for (int i = 0; i <= length; i++) {
            if (i < length && Character.isLetter(paragraph.charAt(i))) {
                sb.append(Character.toLowerCase(paragraph.charAt(i)));
            } else if (sb.length() > 0) {
                String word = sb.toString();
                if (!bannedSet.contains(word)) {
                    int frequency = frequencies.getOrDefault(word, 0) + 1;
                    frequencies.put(word, frequency);
                    maxFrequency = Math.max(maxFrequency, frequency);
                }
                sb.setLength(0);
            }
        }
        String mostCommon = "";
        Set<Map.Entry<String, Integer>> entries = frequencies.entrySet();
        for (Map.Entry<String, Integer> entry : entries) {
            String word = entry.getKey();
            int frequency = entry.getValue();
            if (frequency == maxFrequency) {
                mostCommon = word;
                break;
            }
        }
        return mostCommon;
    }
}