Most frequent word in an array of strings

Given an array of words arr[],  The task is to find the most occurring word in arr[].

Examples: 

Input : arr[] = {“neveropen”, “for”, “neveropen”, “a”, 
                        “portal”, “to”, “learn”, “can”,
                        “be”, “computer”, “science”, 
                        “zoom”, “yup”, “fire”, “in”, 
                        “be”, “data”, “neveropen”}
Output : neveropen 
Explanation : “neveropen” is the most frequent word in the given array occurring 3 times

Input:  arr[] = {“hello”, “world”}
Output: world

Most frequent word in an array of strings By Using Nested Loops:

The idea is to run a loop for each word and count the frequency of the word using a nested loop

Follow the below steps to Implement the idea:

• Traverse a loop for each word in the given array
• Run a nested loop and count the frequency of the word
• Initialize res = “” and freq = 0, to store the resulting string and the frequency of the string.
• If the frequency of the word is greater than the freq
  • Update freq to the frequency of current word.
  • Update res to current word.
• Print res and freq as the final answer.

Below is the Implementation of the above approach. 

The word that occurs most is : neveropen
No of times: 2

Time Complexity: O(N*N), when N is the size of the given array.
Auxiliary Space: O(1)

Most frequent word in an array of strings By Using 2 Hashmaps:

The Idea is to maintain 2 Hashmaps, one to record the first occurrence of the word and second to count the frequency of the word.

Follow the below steps to Implement the idea:

• Initialize two Hashmaps freq and occurrence.
• Initialize result = “”, max =  0, and k = 1.
• Traverse a loop from 1 till N
  • If the current word exist in the occurrence hashmap:
    • then continue.
  • Else update occurrence[arr[i]] = k
  • Increment k by 1
• Traverse another loop from 1 till N
  • Increment the count of the current element in freq by 1
  • If max <= freq[arr[i]]
    • if max < freq[arr[i]]
      • Update max = freq[arr[i]]
      • Update result = arr[i]
    • Else 
      • if occurrence[result] < occurrence[freq[arr[i]]]
        • Update max = freq[arr[i]]
        • Update result = arr[i]
• Return result.

Below is the implementation of the above approach:

neveropen

Time complexity: O(N), where N is the size of the given array.
Auxiliary Space: O(N)

Most frequent word in an array of strings By Using single Hashmap:

The idea is to use a Hashmap to store the frequency of the words and find the word with the maximum frequency from the hashmap.

Follow the below steps to Implement the idea:

• Initialize a HashMap to store the frequency of the words.
• Traverse a loop from 1 till N
  • Increment the count of current word in the Hashmap.
• Initialize key = “” and value = 0
• Traverse the Hashmap
  • If the frequency of the current word is greater than value
    • Update value to frequency of current character
    • Update key as the current word
• return key.

 Below is the implementation of the above approach. 

neveropen

Time Complexity: O(N), where N is the size of the given array.
Auxiliary Space: O(N)

Most frequent word in an array of strings By Using  Trie data structure:

The Idea is to store the count of each element and a string variable to keep track of the most occurring element in the array.

Follow the below steps to Implement the idea:

• Initialize a Trie root.
• Traverse the words in the given array
  • Insert the word in Trie
  • Increment the count of current word by 1
  • If the maxCount < count of current word
    • Update maxCount to current word count.
    • Update maxFrequentString as the current word.
• Print maxFrequentString and maxCount.

Below is the implementation of the above approach.

The word that occurs most is : neveropen
No of times: 3

Time complexity: O(W*L), where W is the number of words in the given array and L is the length of the words.
Auxiliary Space: O(W*L)

This article is contributed by Aarti_Rathi and Pranav. If you like neveropen and would like to contribute, you can also write an article using write.neveropen.co.za or mail your article to review-team@neveropen.co.za. See your article appearing on the neveropen main page and help other Geeks.