49.Group-Anagrams.md

49. Group Anagrams

題目

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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 <= 10^4
• 0 <= strs[i].length <= 100
• strs[i] consists of lowercase English letters.

思路

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Code

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• GoLang

  Runtime 10ms Beats 99.73%

  Memory 7.81mb Beats 55.78%

  Time Complexity: O(m * n* 26) , m is number of strings, n is average length of string.

  Space Complexity: O(m*n) , m is number of strings, n is average length of string.

  func groupAnagrams(strs []string) [][]string {
      anagramsMap := make(map[[26]int][]string)
      
      for _, s := range strs {
          var count [26]int
          for _, c := range s {
              count[c - 'a']++
          }
  
          anagramsMap[count] = append(anagramsMap[count], s)
      }
  
      result := make([][]string, len(anagramsMap))
      index := 0
      for _, v := range anagramsMap {
          result[index] = v
          index++
      }
  
      return result
  }

Reference

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• https://www.youtube.com/watch?v=vzdNOK2oB2E&ab_channel=NeetCode