LeetCode-in-All

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

/**
 * @param {string[]} strs
 * @return {string[][]}
 */
var groupAnagrams = function(strs) {
    const anagrams = new Map()

    for (const word of strs) {
        const freq = new Array(26).fill(0)
        for (const char of word) {
            freq[char.charCodeAt(0) - 'a'.charCodeAt(0)]++
        }
        const keyString = freq.join(',')

        if (!anagrams.has(keyString)) {
            anagrams.set(keyString, [])
        }
        anagrams.get(keyString).push(word)
    }

    return Array.from(anagrams.values())
};

export { groupAnagrams }

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