Given an array arr[] containing N email addresses with different domains, the task is to find the unique domains and their frequencies from the list of emails.
Note: The occurrence of the domain must be printed in the lexicographical order of domain names.
Examples:
Input: arr[] = { “rupesh@gmail.com”, “akole@yahoo.com”, “rupesh.21910879@viit.ac.in”,
“faculty.surname@viit.ac.in”, “Shyam@gmail.com”, “examcell@viit.ac.in”}
Output: gmail.com 2
viit.ac.in 3
yahoo.com 1
Explanation: Here the unique domains in lexicographical order from the list of emails are:
gmail.com, viit.ac.in, yahoo.com.
And their respective frequency in the list is 2, 3 and 1.Input: arr[] = {“neveropen@neveropen.co.za”, “google@gmail.com”}
Output: neveropen.co.za 1
gmail.com 1
Approach: The solution to the problem is based on the following idea:
The domains of an email are mentioned after the ‘@’ symbol. So, find all the domains and store their frequencies.
Follow the steps mentioned below to implement the idea:
- Initialize a map to store the frequencies of each unique domain in the lexicographical order of domain names.
- Transverse each of the email entries:
- For each entry find the index (say idx) of the ‘@’ symbol.
- The substring starting from idx+1 till the end of the string is the domain name.
- Store this domain in the map and increase its frequency by 1.
- Iterate the map from start (as the key are already in sorted order) and print the domain names and their frequencies.
Below is the implementation of the above approach.
C++
// C++ code to implement the approach#include <bits/stdc++.h>using namespace std;// Function to find the unique domains// and their frequenciesvector<pair<string, int> > finddomains( vector<string> input){ // Map to store unique domains // and their frequency map<string, int> domainFre; vector<pair<string, int> > ans; // Loop to find the unique domains for (int i = 0; i < input.size(); i++) { // Find the index of '@' symbol in string auto findindex = input[i].find('@'); // Push the substring starting from // findindex + 1 till the end // and then increase its frequency by 1 domainFre[input[i].substr(findindex + 1)]++; } // Store the key value pair into // vector and finally return it. for (auto it : domainFre) ans.push_back({ it.first, it.second }); // Return the domains and their frequencies return ans;}// Driver codeint main(){ vector<string> input = { "rupesh@gmail.com", "akole@yahoo.com", "rupesh.21910879@viit.ac.in", "faculty.surname@viit.ac.in", "Shyam@gmail.com", "examcell@viit.ac.in" }; vector<pair<string, int> > ans; // Function call ans = finddomains(input); // Print the unique domains and // their frequencies // in lexicographical order for (int i = 0; i < ans.size(); i++) cout << ans[i].first << " " << ans[i].second << endl; return 0;} |
Java
// Java code to implement the approachimport java.io.*;import java.util.*;class pair { String first; int second; pair(String first, int second) { this.first = first; this.second = second; }}class GFG { // Function to find the unique domains // and their frequencies public static ArrayList<pair> finddomains(String[] input) { // Map to store unique domains // and their frequency TreeMap<String, Integer> domainFre = new TreeMap<String, Integer>(); ArrayList<pair> ans = new ArrayList<>(); // Loop to find the unique domains for (int i = 0; i < input.length; i++) { // Find the index of '@' symbol in string int findindex = input[i].indexOf('@'); // Push the substring starting from // findindex + 1 till the end // and then increase its frequency by 1 String temp = input[i].substring(findindex + 1); if (domainFre.get(temp) != null) { domainFre.put(temp, domainFre.get(temp) + 1); } else { domainFre.put(temp, 1); } } // Store the key value pair into // vector and finally return it. for (Map.Entry<String, Integer> it : domainFre.entrySet()) ans.add(new pair(it.getKey(), it.getValue())); // Return the domains and their frequencies return ans; } // Driver Code public static void main(String[] args) { String input[] = { "rupesh@gmail.com", "akole@yahoo.com", "rupesh.21910879@viit.ac.in", "faculty.surname@viit.ac.in", "Shyam@gmail.com", "examcell@viit.ac.in" }; // Function call ArrayList<pair> ans = finddomains(input); // Print the unique domains and // their frequencies // in lexicographical order for (int i = 0; i < ans.size(); i++) System.out.println(ans.get(i).first + " " + ans.get(i).second); }}// This code is contributed by Rohit Pradhan |
Python3
# Python3 code to implement the approach# function to find the unique domains# and their frequenciesdef finddomains(input_): # map to store unique domains # and their frequency domainFre = dict() ans = [] # loop to find the unique domains for i in range(len(input_)): # find the index of '@' symbol in the string findindex = input_[i].index('@') # Push the substring starting from # findindex + 1 till the end # and then increase its frequency by 1 if input_[i][findindex + 1::] in domainFre: domainFre[input_[i][findindex + 1::]] += 1 else: domainFre[input_[i][findindex + 1::]] = 1 # store the key value pair into the # ans list and finally return it for it in domainFre: ans.append([it, domainFre[it]]) # sorting the ans list ans.sort() return ans# Driver Codeinput_ = ["rupesh@gmail.com", "akole@yahoo.com", "rupesh.21910879@viit.ac.in", "faculty.surname@viit.ac.in", "Shyam@gmail.com", "examcell@viit.ac.in"]ans = []# Function callans = finddomains(input_)# Print the unique domains and# their frequencies# in lexicographical orderfor i in range(len(ans)): print(ans[i][0], ans[i][1]) # This code is contributed by phasing17 |
C#
// C# program to implement above approachusing System;using System.Collections;using System.Collections.Generic;class GFG{ // Function to find the unique domains // and their frequencies public static List<pair> finddomains(String[] input) { // Map to store unique domains // and their frequency SortedDictionary<String, int> domainFre = new SortedDictionary<String, int>(); List<pair> ans = new List<pair>(); // Loop to find the unique domains for (int i = 0 ; i < input.Length ; i++) { // Find the index of '@' symbol in string int findindex = input[i].IndexOf('@'); // Push the substring starting from // findindex + 1 till the end // and then increase its frequency by 1 String temp = input[i].Substring(findindex + 1); if (domainFre.ContainsKey(temp)) { domainFre[temp]+=1; } else { domainFre.Add(temp, 1); } } // Store the key value pair into // vector and finally return it. foreach (KeyValuePair<String, int> it in domainFre) ans.Add(new pair(it.Key, it.Value)); // Return the domains and their frequencies return ans; } // Driver Code public static void Main(string[] args){ String[] input = new String[]{ "rupesh@gmail.com", "akole@yahoo.com", "rupesh.21910879@viit.ac.in", "faculty.surname@viit.ac.in", "Shyam@gmail.com", "examcell@viit.ac.in" }; // Function call List<pair> ans = finddomains(input); // Print the unique domains and // their frequencies // in lexicographical order for (int i = 0 ; i < ans.Count ; i++){ Console.WriteLine(ans[i].first + " " + ans[i].second); } }}public class pair{ public String first; public int second; public pair(String first, int second) { this.first = first; this.second = second; }}// This code is contributed by subhamgoyal2014. |
Javascript
<script> // JavaScript code to implement the approach // Function to find the unique domains // and their frequencies const finddomains = (input) => { // Map to store unique domains // and their frequency let domainFre = {}; let ans = []; // Loop to find the unique domains for (let i = 0; i < input.length; i++) { // Find the index of '@' symbol in string let findindex = input[i].indexOf('@'); // Push the substring starting from // findindex + 1 till the end // and then increase its frequency by 1 if (input[i].substring(findindex + 1) in domainFre) domainFre[input[i].substring(findindex + 1)]++; else domainFre[input[i].substring(findindex + 1)] = 1; } // Store the key value pair into // vector and finally return it. for (let it in domainFre) ans.push([it, domainFre[it]]); // Return the domains and their frequencies return ans.sort(); } // Driver code let input = [ "rupesh@gmail.com", "akole@yahoo.com", "rupesh.21910879@viit.ac.in", "faculty.surname@viit.ac.in", "Shyam@gmail.com", "examcell@viit.ac.in" ]; let ans = []; // Function call ans = finddomains(input); // Print the unique domains and // their frequencies // in lexicographical order for (let i = 0; i < ans.length; i++) document.write(`${ans[i][0]} ${ans[i][1]}<br/>`);// This code is contributed by rakeshsahni</script> |
Output
gmail.com 2 viit.ac.in 3 yahoo.com 1
Time Complexity: O(N * M) where M is the average string size
Auxiliary Space: O(K) where K is the number of unique domains
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