Submissions for HackerRank

.HackerRank - Exercises.md

HackerRank - Python Exercises

Python

• Athlete Sort.py
• Finding the percentage.py
• ginortS.py
• Re.start() & Re.end().py
• Reduce Function.py
• Regex Substitution.py
• String Split and Join.py
• Validating Credit Card Numbers.py
• Words Score.py

SQL

• Department Summary.sql
• New Companies.sql
• Placements.sql
• Scheduling Errors.sql
• The Report.sql

Athlete Sort.py

#https://www.hackerrank.com/challenges/python-sort-sort/problem
#!/bin/python3

import math
import os
import random
import re
import sys



if __name__ == '__main__':
    nm = input().split()

    n = int(nm[0])

    m = int(nm[1])

    arr = []

    for _ in range(n):
        arr.append(list(map(int, input().rstrip().split())))

    k = int(input())
    
    for j in sorted(arr, key = lambda x: x[k]):
        print(*j)

Department Summary.sql

SELECT department.name, COUNT(employee.id) AS numberOfEmployees
FROM department
LEFT JOIN employee ON department.id = employee.dept_id
GROUP BY department.name
ORDER BY numberOFEmployees DESC, department.name ASC

Finding the percentage.py

if __name__ == '__main__':
    n = int(input())
    student_marks = {}
    for _ in range(n):
        name, *line = input().split()
        scores = list(map(float, line))
        student_marks[name] = scores
    query_name = input()
    
# extract the values into a list
query_scores = student_marks[query_name]

# sum the scores in the list
total_scores = sum(query_scores)

# convert the floats to decimals and average the scores
from decimal import Decimal
avg = Decimal(total_scores/3)

# Print the mean of the scores, correct to two decimals
print(round(avg,2))

ginortS.py

#https://www.hackerrank.com/challenges/ginorts/problem
# Enter your code here. Read input from STDIN. Print output to STDOUT
import re

s = input()
l = sorted(re.findall('[a-z]', s)) + sorted(re.findall('[A-Z]', s)) + sorted(re.findall('[13579]', s)) + sorted(re.findall('[24680]', s))

print(''.join(l))

New Companies.sql

--https://www.hackerrank.com/challenges/the-company/problem
SELECT 
    c.company_code
    , c.founder
    , COUNT(DISTINCT e.lead_manager_code)
    , COUNT(DISTINCT e.senior_manager_code)
    , COUNT(DISTINCT e.manager_code)
    , COUNT(DISTINCT e.employee_code)
FROM company c
INNER JOIN employee e
ON e.company_code = c.company_code
GROUP BY c.company_code, c.founder
ORDER BY c.company_code;

Placements.sql

--https://www.hackerrank.com/challenges/placements/problem
SELECT s.name
FROM students s
INNER JOIN friends f
ON s.id = f.id
INNER JOIN packages p_student
ON s.id = p_student.id
INNER JOIN packages p_friend
ON f.friend_id = p_friend.id
WHERE 
1 = 1
AND p_student.salary < p_friend.salary
ORDER BY p_friend.salary;

Re.start() & Re.end().py

# https://www.hackerrank.com/challenges/re-start-re-end/problem
import re

S = input()
k = input()
m = re.search(k, S)
pattern = re.compile(k)

if not m: 
    print("(-1, -1)")
while m:
    print("({0}, {1})".format(m.start(), m.end()-1))
    m = pattern.search(S, m.start()+1)

Reduce Function.py

#https://www.hackerrank.com/challenges/reduce-function/problem

from fractions import Fraction
from functools import reduce

def product(fracs):
    t = reduce(lambda fraction1,fraction2:fraction1* fraction2,fracs)
    return t.numerator, t.denominator

if __name__ == '__main__':

Regex Substitution.py

#https://www.hackerrank.com/challenges/re-sub-regex-substitution/problem
# Enter your code here. Read input from STDIN. Print output to STDOUT
import re

s = int(input())

for i in range(s):
    pattern1 = re.compile(r'(?<= )(&&)(?= )')
    pattern2 = re.compile(r'(?<= )(\|\|)(?= )')
    print(pattern2.sub('or', pattern1.sub('and', input())))

Scheduling Errors.sql

SELECT DISTINCT prof.name AS "PROFESSOR.NAME", cou.name AS "COURSE.NAME"
FROM professor prof
INNER JOIN schedule sch 
ON sch.professor_id = prof.id
INNER JOIN course cou 
ON sch.course_id = cou.id
WHERE cou.department_id <> prof.department_id;

String Split and Join.py

#https://www.hackerrank.com/challenges/python-string-split-and-join/problem
def split_and_join(line):
    a = line.split(" ")
    a = "-".join(a)
    return a

if __name__ == '__main__':
    line = input()
    result = split_and_join(line)
    print(result)

The Report.sql

--https://www.hackerrank.com/challenges/the-report/problem
SELECT IF(GRADE < 8, NULL, NAME), GRADE, MARKS
FROM STUDENTS INNER JOIN GRADES
WHERE 
    1 = 1
    AND MARKS BETWEEN MIN_MARK AND MAX_MARK
ORDER BY GRADE DESC, NAME

Validating Credit Card Numbers.py

#https://www.hackerrank.com/challenges/validating-credit-card-number/problem
# Enter your code here. Read input from STDIN. Print output to STDOUT
import re

valid_card = r"^[456]\d{3}(-\d{4}){3}$|^[456]\d{15}$"
no_repeats = r"(\d)(-?\1){3}"

for i in range(int(input())):
    card = input()
    print(f'{"Valid" if (re.match(valid_card, card) and not re.search(no_repeats, card)) else "Invalid"}')

Words Score.py

#https://www.hackerrank.com/challenges/words-score/problem
def is_vowel(letter):
    return letter in ['a', 'e', 'i', 'o', 'u', 'y']

def score_words(words):
    score = 0
    for word in words:
        num_vowels = 0
        for letter in word:
            if is_vowel(letter):
                num_vowels += 1
        if num_vowels % 2 == 0:
            score += 2
        else:
            score += 1
    return score


n = int(input())
words = input().split()
print(score_words(words))