LeetCode in Kotlin

884. Uncommon Words from Two Sentences

Easy

A sentence is a string of single-space separated words where each word consists only of lowercase letters.

A word is uncommon if it appears exactly once in one of the sentences, and does not appear in the other sentence.

Given two sentences s1 and s2, return a list of all the uncommon words. You may return the answer in any order.

Example 1:

Input: s1 = “this apple is sweet”, s2 = “this apple is sour”

Output: [“sweet”,”sour”]

Example 2:

Input: s1 = “apple apple”, s2 = “banana”

Output: [“banana”]

Constraints:

• 1 <= s1.length, s2.length <= 200
• s1 and s2 consist of lowercase English letters and spaces.
• s1 and s2 do not have leading or trailing spaces.
• All the words in s1 and s2 are separated by a single space.

Solution

class Solution {
    fun uncommonFromSentences(s1: String, s2: String): Array<String?> {
        val visited = HashSet<String>()
        val uniques = HashSet<String>()
        for (word in s1.split(" ".toRegex()).dropLastWhile { it.isEmpty() }.toTypedArray()) {
            if (!visited.add(word)) {
                uniques.remove(word)
            } else {
                uniques.add(word)
            }
        }
        for (word in s2.split(" ".toRegex()).dropLastWhile { it.isEmpty() }.toTypedArray()) {
            if (!visited.add(word)) {
                uniques.remove(word)
            } else {
                uniques.add(word)
            }
        }
        val arr = arrayOfNulls<String>(uniques.size)
        for ((i, word) in uniques.withIndex()) {
            arr[i] = word
        }
        return arr
    }
}

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