Day 28: RegEx, Patterns, and Intro to Databases

Objective
Today, we're working with regular expressions. Check out the Tutorial tab for learning materials and an instructional video!

Task
Consider a database table, Emails, which has the attributes First Name and Email ID. Given  rows of data simulating the Emails table, print an alphabetically-ordered list of people whose email address ends in .

Input Format

The first line contains an integer, , total number of rows in the table.
Each of the  subsequent lines contains  space-separated strings denoting a person's first name and email ID, respectively.

Constraints

• Each of the first names consists of lower case letters  only.
• Each of the email IDs consists of lower case letters ,  and  only.
• The length of the first name is no longer than 20.
• The length of the email ID is no longer than 50.

Output Format

Print an alphabetically-ordered list of first names for every user with a gmail account. Each name must be printed on a new line.

Sample Input

6
riya riya@gmail.com
julia julia@julia.me
julia sjulia@gmail.com
julia julia@gmail.com
samantha samantha@gmail.com
tanya tanya@gmail.com

Sample Output

julia
julia
riya
samantha
tanya

Solution :

#include <bits/stdc++.h>

using namespace std;

int main()
{
    int N;
    cin >> N;
    
    vector<string> names;
    
    string name, email;
    regex r(".+@gmail\\.com$");
    for (int i=0; i<N; i++)
    {
        cin >> name >> email;
        if (regex_match(email,r))
            names.push_back(name);
    }
    
    sort(names.begin(), names.end());
    int s = names.size();
    
    for (int i=0; i<s; i++)
        cout << names[i]<<"\n";
    
    return 0;
}