Group Anagrams

Description

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 lower-case English letters.

Solution(javascript)

/**
 * @param {string[]} strs
 * @return {string[][]}
 */
const groupAnagrams = function (strs) {
  const sortStr = str => str.split('').sort((a, b) => a.localeCompare(b)).join('')
  const sortedMap = strs.map(sortStr).reduce(
    (map, current, index) => {
      if (map[current]) {
        map[current].push(strs[index])
      } else {
        map[current] = [strs[index]]
      }
      return map
    },
    {},
  )
  return Object.keys(sortedMap).map(key => sortedMap[key])
}