Given two sentenceswords1, words2(each represented as an array of strings), and a list of similar word pairspairs, determine if two sentences are similar.

For example, "great acting skills" and "fine drama talent" are similar, if the similar word pairs arepairs = [["great", "fine"], ["acting","drama"], ["skills","talent"]].

Note that the similarity relation is not transitive. For example, if "great" and "fine" are similar, and "fine" and "good" are similar, "great" and "good" arenotnecessarily similar.

However, similarity is symmetric. For example, "great" and "fine" being similar is the same as "fine" and "great" being similar.

Also, a word is always similar with itself. For example, the sentenceswords1 = ["great"], words2 = ["great"], pairs = []are similar, even though there are no specified similar word pairs.

Finally, sentences can only be similar if they have the same number of words. So a sentence likewords1 = ["great"]can never be similar towords2 = ["doubleplus","good"].

Note:

The length of

words1

and

words2

will not exceed

1000

.

The length of

pairs

will not exceed

2000

.

The length of each

pairs[i]

will be

2

.

The length of each

words[i]

and

pairs[i][j]

will be in the range

[1, 20]

.

class Solution {
    public boolean areSentencesSimilar(
            String[] words1, String[] words2, String[][] pairs) {
        if (words1.length != words2.length) return false;

        Set<String> pairset = new HashSet();
        for (String[] pair: pairs)
            pairset.add(pair[0] + "#" + pair[1]);

        for (int i = 0; i < words1.length; ++i) {
            if (!words1[i].equals(words2[i]) &&
                    !pairset.contains(words1[i] + "#" + words2[i]) &&
                    !pairset.contains(words2[i] + "#" + words1[i]))
                return false;
        }
        return true;
    }
}