734. Sentence Similarity

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734. Sentence Similarity

Description

We can represent a sentence as an array of words, for example, the sentence "I am happy with leetcode" can be represented as arr = ["I","am",happy","with","leetcode"].

Given two sentences sentence1 and sentence2 each represented as a string array and given an array of string pairs similarPairs where similarPairs[i] = [xi, yi] indicates that the two words xi and yi are similar.

Return true if sentence1 and sentence2 are similar, or false if they are not similar.

Two sentences are similar if:

  • They have the same length (i.e., the same number of words)
  • sentence1[i] and sentence2[i] are similar.

Notice that a word is always similar to itself, also notice that the similarity relation is not transitive. For example, if the words a and b are similar, and the words b and c are similar, a and c are not necessarily similar .

Example 1:

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Input: sentence1 = ["great","acting","skills"], sentence2 = ["fine","drama","talent"], similarPairs = [["great","fine"],["drama","acting"],["skills","talent"]]
Output: true
Explanation: The two sentences have the same length and each word i of sentence1 is also similar to the corresponding word in sentence2.

Example 2:

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Input: sentence1 = ["great"], sentence2 = ["great"], similarPairs = []
Output: true
Explanation: A word is similar to itself.

Example 3:

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Input: sentence1 = ["great"], sentence2 = ["doubleplus","good"], similarPairs = [["great","doubleplus"]]
Output: false
Explanation: As they don't have the same length, we return false.

Constraints:

  • 1 <= sentence1.length, sentence2.length <= 1000
  • 1 <= sentence1[i].length, sentence2[i].length <= 20
  • sentence1[i] and sentence2[i] consist of English letters.
  • 0 <= similarPairs.length <= 1000
  • similarPairs[i].length == 2
  • 1 <= x<sub>i</sub>.length, y<sub>i</sub>.length <= 20
  • x<sub>i</sub> and y<sub>i</sub> consist of lower-case and upper-case English letters.
  • All the pairs (x<sub>i</sub>,<sub> </sub>y<sub>i</sub>) are distinct .

Hints/Notes

  • record the mapping and compare each word

Solution

Language: C++

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class Solution {
public:
    bool areSentencesSimilar(vector<string>& sentence1, vector<string>& sentence2, vector<vector<string>>& similarPairs) {
        if (sentence1.size() != sentence2.size()) {
            return false;
        }
        unordered_map<string, set<string>> mapping;
        for (auto pair : similarPairs) {
            mapping[pair[0]].insert(pair[1]);
            mapping[pair[1]].insert(pair[0]);
        }

        for (int i = 0; i < sentence1.size(); i++) {
            if (sentence1[i] == sentence2[i]) {
                continue;
            }
            string w1 = sentence1[i];
            string w2 = sentence2[i];
            if (!mapping[w1].count(w2)) {
                return false;
            }
        }
        return true;
    }
};