GroupAnagrams.swift

/**
 * Question Link: https://leetcode.com/problems/anagrams/
 * Primary idea: Iterate the string array and categories strings with the same sorted one
 *
 * Time Complexity: O(nmlogm + nlogn), n stands for number of words, m stands for the length of a word
 *                  Space Complexity: O(n)
 */

class GroupAnagrams {
    func groupAnagrams(_ strs: [String]) -> [[String]] {
        var map = [String: [String]]()
  
        for str in strs {
            let sortedStr = String(str.sorted())
    
            var anagrams = [String]()
            if let list = map[sortedStr] {
                anagrams = list
            }
            anagrams.append(str)
            map[sortedStr] = anagrams
        }
  
        return map.values.map { value in value.sorted() }
    }
}