LeetCode Entry

884. Uncommon Words from Two Sentences

17.09.2024 easy 2024 kotlin rust

Unique words from two strings

884. Uncommon Words from Two Sentences easy blog post substack youtube 1.webp

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Problem TLDR

Unique words from two strings #easy

Intuition

We can count frequencies by using a HashMap

Approach

  • treat two strings like a single, no difference
  • there is a groupBy in Kotlin (in Rust it is in external crate itertools)
  • c++ has a stringstream

Complexity

  • Time complexity: \(O(n)\)

  • Space complexity: \(O(n)\)

Code


    fun uncommonFromSentences(s1: String, s2: String) =
        "$s1 $s2".split(" ").groupBy { it }
        .filter { (k, v) -> v.size < 2 }.keys.toList()



    pub fn uncommon_from_sentences(s1: String, s2: String) -> Vec<String> {
        let mut freq = HashMap::new();
        for w in s1.split_whitespace() { *freq.entry(w).or_insert(0) += 1 }
        for w in s2.split_whitespace() { *freq.entry(w).or_insert(0) += 1 }
        freq.into_iter().filter(|(k, v)| *v == 1).map(|(k, v)| k.to_string()).collect()
    }



    vector<string> uncommonFromSentences(string s1, string s2) {
        unordered_map<string, int> freq; vector<string> res;
        string s = s1 + " " + s2; stringstream ss(s); string w;
        while (getline(ss, w, ' ')) ++freq[w];
        for (auto kv: freq) if (kv.second == 1) res.push_back(kv.first);
        return res;
    }