HackerRank Day 28: RegEx Patterns and Intro to Database 30 days of code solution

Today we are going to solve HackerRank Day 28: RegEx Patterns and Intro to Database 30 days of code solutions in C, C++, Java, Javascript & Python.

Objective

Today, we’re working with regular expressions.

Task

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

Input Format

The first line contains an integer, N, total number of rows in the table.
Each of the N subsequent lines contains 2 space-separated strings denoting a person’s first name and email ID, respectively.

Constraints

• 2 <= N <= 30
• Each of the first names consists of lowercase letters [a – z] only.
• Each of the email IDs consists of lowercase letters [a – z], @ 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

HackerRank Day 28: RegEx Patterns and Intro to Database 30 days of code solutions

RegEx Patterns and Intro to Database Solutions in C

#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>
#include <ctype.h>

int mycmp(const char *a, const char *b) {
    const char *cp1 = a, *cp2 = b;

    for (; toupper(*cp1) == toupper(*cp2); cp1++, cp2++)
        if (*cp1 == '\0')
            return 0;
    return ((toupper(*cp1) < toupper(*cp2)) ? -1 : +1);
} 

int cmp(const void *p1, const void *p2) {
    return mycmp(* (char * const *) p1, * (char * const *) p2);
}

char* validate_local_address(char* email) {
    char *ptr;
    for (ptr = email; *ptr; ptr++) {
        if (*ptr == '@' && ptr != email) {
            // check that we saw at least one character
            return ptr+1;
        } else if (!((*ptr >= 'a' && *ptr <= 'z') || (*ptr == '.'))) {
            return 0;
        }
    }
    return 0;
}

int main(){
    int N; 
    scanf("%d",&N);
    char **result = (char **)malloc(N * sizeof(char *));
    int index = 0;
    for(int a0 = 0; a0 < N; a0++){
        char* firstName = (char *)malloc(1024 * sizeof(char));
        memset(firstName, 0, 1024);
        
        char* emailID = (char *)malloc(1024 * sizeof(char));
        memset(emailID, 0, 1024);
        
        scanf("%s %s",firstName,emailID);
        int len = strlen(emailID);
        if (strlen(firstName)) {
            char *ptr = validate_local_address(emailID);
            if (ptr) {
                if (!strcmp(ptr, (const char *)"gmail.com")) {
                    char *p = firstName;
                    for ( ; *p; ++p) *p = tolower(*p);
                    result[index++] = firstName;
                }
            }
        }
    }
    
    if (index) {
        // sort the names alphabetically
        qsort(result, index, sizeof(char *), cmp);
        
        int i;
        for (i = 0; i < index; i++) {
            printf("%s\n", result[i]);
        }
    }
    
    return 0;
}

RegEx Patterns and Intro to Database Solution in C++

#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;

bool end_with(string& s) {
    string t = "@gmail.com";
    if (s.size() < t.size()) return false;
    for (int i = s.size() - 1, j = t.size() - 1; i >= 0 && j >= 0; --i, --j) {
        if (s[i] != t[j]) return false;
    }
    return true;
}
int main(){
    int N;
    cin >> N;
    vector<string> ans;
    for(int a0 = 0; a0 < N; a0++){
        string firstName;
        string emailID;
        cin >> firstName >> emailID;
        if (end_with(emailID))
            ans.push_back(firstName);
    }
    sort(ans.begin(), ans.end());
    for (int i = 0; i < ans.size(); ++i)
        cout << ans[i] << endl;
    return 0;
}

RegEx Patterns and Intro to Database Solution in Java

import java.io.*;
import java.util.*;

public class Solution {

    public static void main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        in.nextLine();
        
        ArrayList<String> results = new ArrayList<String>();
        
        for (int i = 0; i < n; i++) {
            String line = in.nextLine();
            String[] tokens = line.split(" ");
            if (tokens[1].endsWith("@gmail.com"))
                results.add(tokens[0]);
        }
        
        Collections.sort(results);
        for (String s : results) {
            System.out.println(s);
        }
    }
}

RegEx Patterns and Intro to Database Solution in Javascript

process.stdin.resume();
process.stdin.setEncoding('ascii');

var input_stdin = "";
var input_stdin_array = "";
var input_currentline = 0;

process.stdin.on('data', function (data) {
    input_stdin += data;
});

process.stdin.on('end', function () {
    input_stdin_array = input_stdin.split("\n");
    main();    
});

function readLine() {
    return input_stdin_array[input_currentline++];
}

/////////////// ignore above this line ////////////////////

function main() {
    var N = parseInt(readLine());
    var patt = new RegExp("@gmail.com");
    var names = [];
    for(var a0 = 0; a0 < N; a0++){
        var firstName_temp = readLine().split(' ');
        var firstName = firstName_temp[0];
        var emailID = firstName_temp[1];
        if(patt.test(emailID)){
            names.push(firstName);
        }
    }
    names.sort().forEach(function(name){
        console.log(name);
    });
}

RegEx Patterns and Intro to Database Solution in Python 2

#!/bin/python

import sys


N = int(raw_input().strip())
nameList = []
for a0 in xrange(N):
    firstName,emailID = raw_input().strip().split(' ')
    firstName,emailID = [str(firstName),str(emailID)]
    if (emailID.split('@')[1] == 'gmail.com'):
        nameList.append(firstName)
nameList = sorted(nameList)
for name in nameList:
    print name

RegEx Patterns and Intro to Database Solution in Python 3

#!/bin/python3

import math
import os
import random
import re
import sys



if __name__ == '__main__':
    N = int(input())
    nw = []

    for N_itr in range(N):
        firstNameEmailID = input().split()

        firstName = firstNameEmailID[0]

        emailID = firstNameEmailID[1]
        if '@gmail.com' in emailID:
            nw.append(firstName)
    
    nw = sorted(nw)
    for item in nw:
        print(item)

NEXT: HackerRank Day 29: Bitwise AND 30 days of code solution

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