Write a function | HackerRank

Goal

This task is to return true if a give year is a leap year, otherwise return false

Solution

There are three main conditions to check leap year:

1. It can be evenly divided by 4 - leap year

2. It can be evenly divided by 100, it is NOT a leap year, unless it is evenly disivible by 400 - leap year

3. Otherwise it is not a leap year.

These conditions can be shown in this code.

# Write a function

def is_leap(year):
    leap = False
    
    # Write your logic here
    if year % 4 == 0:
        if year % 100 == 0:
            if year % 400 == 0:
                leap = True
            else : 
                leap = False
        else:  
            leap = True
        
    else:
        leap = False
    
    return leap

year = int(input())
print(is_leap(year))

For Loop | HackerRank

Goal

Print results according to two positive input values by using for loop statement.

Solution

To solve easily, I create vector string array included 1-9 numbers. If you use vector array, you can print numbers easily.

// For Loop
#include <iostream>
#include <cstdio>
#include <vector>
#include <string>
using namespace std;

int main() {
    // Complete the code.
    int a,b;
    cin >> a;
    cin >> b;
    
    vector<string> numbers {"", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine"};
    
    for(int i = a; i <= b; i++){
        
        if(i>9){
            if( i % 2 == 0){
                cout << "even" << endl;
            }
            else{
                cout << "odd" << endl;
            }
        }
        
        else{
            
            cout << numbers[i] << endl;
        }
    }
    
    return 0;
}

https://www.hackerrank.com/challenges/c-tutorial-conditional-if-else/problem

Goal

Solution

You just need to create condtion statements for each condition like below.

// Conditional Statements

#include <bits/stdc++.h>

using namespace std;

string ltrim(const string &);
string rtrim(const string &);



int main()
{
    string n_temp;
    getline(cin, n_temp);

    int n = stoi(ltrim(rtrim(n_temp)));

    // Write your code here
    if(n > 9){
        printf("Greater than 9");
    }
    else if(n == 1){
        printf("one");
    }
    else if(n == 2){
        printf("two");
    }
    else if(n == 3){
        printf("three");
    }
    else if(n == 4){
        printf("four");
    }
    else if(n == 5){
        printf("five");
    }
    else if(n == 6){
        printf("six");
    }
    else if(n == 7){
        printf("seven");
    }
    else if(n == 8){
        printf("eight");
    }
    else { // n == 9
        printf("nine");
    }

    return 0;
}

string ltrim(const string &str) {
    string s(str);

    s.erase(
        s.begin(),
        find_if(s.begin(), s.end(), not1(ptr_fun<int, int>(isspace)))
    );

    return s;
}

string rtrim(const string &str) {
    string s(str);

    s.erase(
        find_if(s.rbegin(), s.rend(), not1(ptr_fun<int, int>(isspace))).base(),
        s.end()
    );

    return s;
}

Basic Data Types | HackerRank

Goal

1. Read space-seprated values : int, long, char, float and double, respectively

2. Print each element on a new line in the same order it was received as input. + correct decimal points of floating and double points.

Solution

Follow HackerRank explanation of c++ data types and their format specifiers.

// Basic Data Types

#include <iostream>
#include <cstdio>
using namespace std;

int main() {
    // Complete the code.
    int a;
    long b;
    char c;
    float d;
    double e;

    scanf("%d %ld %c %f %lf", &a, &b, &c, &d, &e);
    printf("%d\n", a);
    printf("%ld\n", b);
    printf("%c\n", c);
    printf("%f\n", d);
    printf("%lf\n", e);
    return 0;
}

Loops | HackerRank

Goal

Solution

If you know for statement in python, it woul be very easy task.

# Loops

if __name__ == '__main__':
    n = int(input())
    
    for i in range(n):
        print(i * i)

Python: Division | HackerRank

Goal

1. Read two integers each line.

2. print (a//b) in first line.

3. print (a/b) in second line.

Solution

Use input() function to read two integer values. But don't forget to convert input return value into integer value. 

# Python: Division

if __name__ == '__main__':
    a = int(input())
    b = int(input())
    
    print(a // b)
    print(a / b)

Arithmetic Operators | HackerRank

Goal

1. Read two integers from STDIN.

2. Solve tasks to use arithmetic operators. 

Solution

You can read values by using input() function. The important thing is to convert input() value into integer type because Input() function returns string value from input. 

After read two integer values, you can calculate vaules for each task.

# Arithmetic Operators

if __name__ == '__main__':
    a = int(input())
    b = int(input())
    
    sum = a + b
    difference = a - b
    product = a * b
    
    print(sum)
    print(difference)
    print(product)

Python If-Else | HackerRank

Goal

You need to print "Weird" if the number is weird in under condition. Otherweise, print "Not Weird". 

Solution

You can follow what conditions say, then it would be easy.

# Python If-Else

import math
import os
import random
import re
import sys


if __name__ == '__main__':
    n = int(input().strip())
    
    if (n % 2) !=0 : 
        print('Weird')
    else:
        if (n >=2 and n <=5):
            print('Not Weird')
        
        elif (n >=6 and n <=20):
            print('Weird')
            
        else:
            print('Not Weird')

Say "Hello, World!" With Python | HackerRank

Goal

Print "Hello, World!" to stdout. 

Solution

You can use print function to print the specificed message. 

# Say "Hello, World!" With Python

if __name__ == '__main__':
    print("Hello, World!")

Input and Output | HackerRank

Goal

Read 3 numbers from stdin and print their sum to stdout

Solution

This challenge is to practice reading input from stdin(standard input stream) and printing out to stdout(standard output stream).

// Input and Output

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int a, b,c ;
    int result = 0;
    cin >> a >> b >> c;
    result = a + b + c;
    cout << result << endl;
    return 0;
}