Leetcode 题目解析之 Word Pattern

    public boolean wordPattern(String pattern, String str) {
        if (pattern == null || str == null) {
            return false;
        }
        String[] strs = str.split(" ");
        if (pattern.length() != strs.length) {
            return false;
        }
        Map<Character, String> map = new HashMap<Character, String>();
        for (int i = 0; i < pattern.length(); i++) {
            char c = pattern.charAt(i);
            if (map.containsKey(c)) {
                if (!map.get(c).equals(strs[i])) {
                    return false;
                }
            } else {
                // 保证1对1的映射
                if (map.containsValue(strs[i])) {
                    return false;
                }
                map.put(c, strs[i]);
            }
        }
        return true;
    }