734. Sentence Similarity

class Solution {
    public boolean areSentencesSimilar(String[] words1, String[] words2, String[][] pairs) {
        int m = words1.length, n = words2.length;
        if(m != n) return false;
        Map<String, Set<String>> map = new HashMap<>();
        for(String[] pair : pairs)
        {
            String u = pair[0], v = pair[1];
            if(!map.containsKey(u)) map.put(u, new HashSet<>());
            if(!map.containsKey(v)) map.put(v, new HashSet<>());
            map.get(u).add(v);
            map.get(v).add(u);
        }
        for(int i = 0; i < m; i++)
        {
            String w1 = words1[i], w2 = words2[i];
            if(w1.equals(w2) || map.containsKey(w1) && map.get(w1).contains(w2) ||
               map.containsKey(w2) && map.get(w2).contains(w1)) continue;
            return false;
        }
        return true;
    }
}