s0049_group_anagrams

49. Group Anagrams

Medium

Given an array of strings strs, group the anagrams together. You can return the answer in any order.

An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once.

Example 1:

Input: strs = ["eat","tea","tan","ate","nat","bat"]

Output: [["bat"],["nat","tan"],["ate","eat","tea"]]

Example 2:

Input: strs = [""]

Output: [[""]]

Example 3:

Input: strs = ["a"]

Output: [["a"]]

Constraints:

• 1 <= strs.length <= 104
• 0 <= strs[i].length <= 100
• strs[i] consists of lowercase English letters.

Solution

import scala.collection.mutable.{ArrayBuffer, Map}

object Solution {
    def groupAnagrams(strs: Array[String]): List[List[String]] = {
        val hm = Map[String, ArrayBuffer[String]]()

        for (s <- strs) {
            val ch = s.toCharArray
            ch.sortInPlace()
            val temp = new String(ch)
            hm.getOrElseUpdate(temp, ArrayBuffer.empty[String]) += s
        }

        hm.values.map(_.toList).toList
    }
}