Find the word with most anagrams in a given sentence

Difficulty Level : Easy
Last Updated : 18 Feb, 2021

Given a string S in the form of a sentence, the task is to find the word from the text with maximum number of its anagrams present in the given sentence.
Example:

Input: S = “please be silent and listen to what the professor says”
Output: silent
Explanation:
Only the word “silent” has an anagram(listen) present in the sentence.
Input: S = “cat is not a dog and sword has no words when government creates act so what is tac”
Output: cat
Explanation:
The word “cat” has two anagrams (“act”, “tac”) present in the sentence.
The word “words” has an anagram (“sword”) present in the sentence.
Hence, the word with the maximum anagrams is “cat”.

Approach:
Following observations need to be made to solve the program:

Property of Prime Numbers: The product of any combination of prime numbers generates an unique number which cannot be obtained by any other combination of prime numbers.

Follow the steps below to solve the problem:

Assign each alphabet with a distinct prime number.
For each word in the given string, calculate the product of prime numbers assigned to the characters of that word and store it in a HashMap.
Calculate the product of prime numbers assigned to the characters of a word and store it in a HashMap.
Find the product with maximum frequency in the HashMap and print one of the corresponding anagrams as the answer.

Below is the implementation of the above approach:

C++14

// C++ Program to find the word
// with most anagrams in a sentence
#include <bits/stdc++.h>
using namespace std;
 
// Function to find the word with
// maximum number of anagrams
string largestAnagramGrp(vector<string> arr) 
{
   
  // Primes assigned to 26 alphabets
  int prime[] = {2,  3,  5,  7,  11, 13, 17,
                19, 23, 29, 31, 37, 41,
                43, 47, 53, 59, 61, 67, 71,
                73, 79, 83, 89, 97, 101};
  int max = -1;
  long maxpdt = -1;
 
  // Stores the product and
  // word mappings
  unordered_map<long long, string> W;
 
  // Stores the frequencies
  // of products
  unordered_map<long long, long> P;
  for (string temp : arr) 
  {
    long pdt = 1;
 
    // Calculate the product of
    // primes assigned
    for (char t : temp)
    {
      pdt *= prime[t - 'a'];
    }
 
    // If product already exists
    if (P.find(pdt) != P.end())
    {
      P[pdt]++;
    }
 
    // Otherwise
    else
    {
      W[pdt] = temp;
      P[pdt] = 1;
    }
  }
 
  // Fetch the most frequent product
  for (auto e : P) 
  {
    if (max < e.second) 
    {
      max = e.second;
      maxpdt = e.first;
    }
  }
 
  // Return a string
  // with that product
  return W[maxpdt];
}
 
// Driver Code
 
int main()
{
  char S[] = "please be silent and listen to what the professor says ";
  vector<string> arr;
 
  char *token = strtok(S, " ");
  while (token != NULL)
  {
    arr.push_back(token);
    token = strtok(NULL, " ");
  }
 
  cout << largestAnagramGrp(arr) << endl;
  return 0;
}
 
// This code is contributed by
// sanjeev2552

Java

// Java Program to find the word
// with most anagrams in a sentence
import java.util.*;
 
class GFG {
 
    // Function to find the word with
    // maximum number of anagrams
    private static String largestAnagramGrp(
        String arr[])
    {
        // Primes assigned to 26 alphabets
        int prime[]
            = { 2, 3, 5, 7, 11, 13, 17,
                19, 23, 29, 31, 37, 41,
                43, 47, 53, 59, 61, 67, 71,
                73, 79, 83, 89, 97, 101 };
 
        int max = -1;
        long maxpdt = -1;
 
        // Stores the product and
        // word mappings
        HashMap<Long, String> W
            = new HashMap<>();
 
        // Stores the frequencies
        // of products
        HashMap<Long, Integer> P
            = new HashMap<>();
 
        for (String temp : arr) {
            char c[] = temp.toCharArray();
            long pdt = 1;
 
            // Calculate the product of
            // primes assigned
            for (char t : c) {
                pdt *= prime[t - 'a'];
            }
 
            // If product already exists
            if (P.containsKey(pdt)) {
                P.put(pdt, P.get(pdt) + 1);
            }
 
            // Otherwise
            else {
                W.put(pdt, temp);
                P.put(pdt, 1);
            }
        }
 
        // Fetch the most frequent product
        for (Map.Entry<Long, Integer>
                 e : P.entrySet()) {
            if (max < e.getValue()) {
                max = e.getValue();
                maxpdt = e.getKey();
            }
        }
 
        // Return a string
        // with that product
        return W.get(maxpdt);
    }
 
    // Driver Code
    public static void main(String args[])
    {
        String S = "please be silent and listen"
                   + " to what the professor says ";
        String arr[] = S.split("[ ]+");
        System.out.println(largestAnagramGrp(arr));
    }
}

Python3

# Python3 Program to find the word
# with most anagrams in a sentence
 
# Function to find the word with
# maximum number of anagrams
def largestAnagramGrp(arr):
     
    # Primes assigned to 26 alphabets
    prime= [2, 3, 5, 7, 11, 13, 17,
            19, 23, 29, 31, 37, 41,
            43, 47, 53, 59, 61, 67, 71,
            73, 79, 83, 89, 97, 101]
    max = -1
    maxpdt = -1
 
    # Stores the product and
    # word mappings
    W = {}
 
    # Stores the frequencies
    # of products
    P = {}
    for temp in arr:
        c = [i for i in temp]
        pdt = 1
 
        # Calculate the product of
        # primes assigned
        for t in c:
            pdt *= prime[ord(t) - ord('a')]
 
        # If product already exists
        if (pdt in P):
            P[pdt] = P.get(pdt, 0) + 1
 
        # Otherwise
        else:
            W[pdt] = temp
            P[pdt] = 1
 
    # Fetch the most frequent product
    for e in P:
        if (max < P[e]):
            max = P[e]
            maxpdt = e
 
    # Return a string
    # with that product
    return W[maxpdt]
 
# Driver Code
if __name__ == '__main__':
    S = "please be silent and listen to what the professor says"
    arr = S.split(" ")
    print(largestAnagramGrp(arr))
 
    # This code is contributed by mohit kumar 29

C#

// C# program to find the word
// with most anagrams in a sentence
using System;
using System.Collections.Generic;
 
class GFG{
 
// Function to find the word with
// maximum number of anagrams
private static String largestAnagramGrp(String []arr)
{
     
    // Primes assigned to 26 alphabets
    int []prime = { 2, 3, 5, 7, 11, 13, 17,
                    19, 23, 29, 31, 37, 41,
                    43, 47, 53, 59, 61, 67, 71,
                    73, 79, 83, 89, 97, 101 };
 
    int max = -1;
    long maxpdt = -1;
 
    // Stores the product and
    // word mappings
    Dictionary<long, 
               String> W = new Dictionary<long,
                                          String>();
 
    // Stores the frequencies
    // of products
    Dictionary<long, 
               int> P = new Dictionary<long, 
                                       int>();
                                        
    foreach(String temp in arr) 
    {
        char []c = temp.ToCharArray();
        long pdt = 1;
 
        // Calculate the product of
        // primes assigned
        foreach(char t in c)
        {
            pdt *= prime[t - 'a'];
        }
 
        // If product already exists
        if (P.ContainsKey(pdt))
        {
            P[pdt] = P[pdt] + 1;
        }
 
        // Otherwise
        else
        {
            W.Add(pdt, temp);
            P.Add(pdt, 1);
        }
    }
 
    // Fetch the most frequent product
    foreach(KeyValuePair<long, int> e in P)
    {
        if (max < e.Value)
        {
            max = e.Value;
            maxpdt = e.Key;
        }
    }
 
    // Return a string
    // with that product
    return W[maxpdt];
}
 
// Driver Code
public static void Main(String []args)
{
    String S = "please be silent and listen" +
               " to what the professor says ";
                
    String []arr = S.Split(' ');
     
    Console.WriteLine(largestAnagramGrp(arr));
}
}
 
// This code is contributed by sapnasingh4991

Output:

silent

Time Complexity: O(N), N is the length of the string excluding the blankspaces.
Auxiliary Space: O(N)

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