Coding Interview Resources
This channel contains the free resources and solution of coding problems which are usually asked in the interviews. Managed by: @love_data
Mostrar más📈 Análisis del canal de Telegram Coding Interview Resources
El canal Coding Interview Resources (@crackingthecodinginterview) en el segmento lingüístico de Inglés es un actor destacado. Actualmente la comunidad reúne a 52 248 suscriptores, ocupando la posición 2 474 en la categoría Tecnologías y Aplicaciones y el puesto 6 815 en la región India.
📊 Métricas de audiencia y dinámica
Desde su creación el невідомо, el proyecto ha mostrado un crecimiento acelerado, reuniendo a 52 248 suscriptores.
Según los últimos datos del 26 agosto, 2026, el canal mantiene una actividad estable. En los últimos 30 días la variación de miembros fue de 31, y en las últimas 24 horas de -3, conservando un alto alcance.
- Estado de verificación: No verificado
- Tasa de interacción (ER): El promedio de interacción de la audiencia es 1.85%. Durante las primeras 24 horas tras publicar, el contenido suele obtener 0.76% de reacciones respecto al total de suscriptores.
- Alcance de las publicaciones: Cada publicación recibe en promedio 966 visualizaciones. En el primer día suele acumular 398 visualizaciones.
- Reacciones e interacción: La audiencia responde de forma activa: el promedio de reacciones por publicación es 2.
- Intereses temáticos: El contenido se centra en temas clave como array, stack, algorithm, programming, sort.
📝 Descripción y política de contenido
El autor describe el recurso como un espacio para expresar opiniones subjetivas:
“This channel contains the free resources and solution of coding problems which are usually asked in the interviews.
Managed by: @love_data”
Gracias a la alta frecuencia de actualizaciones (últimos datos recibidos el 27 agosto, 2026), el canal mantiene la vigencia y un amplio alcance. La analítica demuestra que la audiencia interactúa activamente con el contenido, lo que lo convierte en un punto de referencia dentro de la categoría Tecnologías y Aplicaciones.
SELECT name, salary
FROM employees;
2. FROM
What it is: Specifies the table
What it does: Tells SQL where to get data from
Query: Fetch all data from employees
SELECT *
FROM employees;
3. WHERE
What it is: Filters rows based on condition
What it does: Returns only matching rows
Query: Employees with salary > 30000
SELECT *
FROM employees
WHERE salary > 30000;
4. ORDER BY
What it is: Sorts the data
What it does: Arranges rows in order
Query: Sort by salary (highest first)
SELECT *
FROM employees
ORDER BY salary DESC;
5. COUNT()
What it is: Counts rows
What it does: Returns total records
Query: Count employees
SELECT COUNT(*)
FROM employees;
6. AVG()
What it is: Calculates average
What it does: Returns mean value
Query: Average salary
SELECT AVG(salary)
FROM employees;
7. GROUP BY
What it is: Groups rows by column
What it does: Applies aggregation per group
Query: Avg salary per department
SELECT department, AVG(salary)
FROM employees
GROUP BY department;
8. HAVING
What it is: Filters grouped data
What it does: Returns filtered groups
Query: Departments with avg salary > 40000
SELECT department, AVG(salary)
FROM employees
GROUP BY department
HAVING AVG(salary) > 40000;
9. INNER JOIN
What it is: Combines matching rows from tables
What it does: Returns common data
Query: Employees with department names
SELECT e.name, d.department_name
FROM employees e
INNER JOIN departments d
ON e.dept_id = d.dept_id;
10. LEFT JOIN
What it is: Combines all left + matching right
What it does: Returns all left table data
Query: All employees with departments
SELECT e.name, d.department_name
FROM employees e
LEFT JOIN departments d
ON e.dept_id = d.dept_id;
11. CASE WHEN
What it is: Conditional logic
What it does: Creates values based on condition
Query: Categorize salary
SELECT name,
CASE
WHEN salary > 40000 THEN 'High'
ELSE 'Low'
END AS category
FROM employees;
12. SUBQUERY
What it is: Query inside another query
What it does: Uses result of inner query
Query: Salary above average
SELECT name, salary
FROM employees
WHERE salary > (
SELECT AVG(salary)
FROM employees
);
13. RANK()
What it is: Window function
What it does: Assigns rank without grouping
Query: Rank employees by salary
SELECT name, salary,
RANK() OVER (ORDER BY salary DESC) AS rank
FROM employees;
14. DISTINCT
What it is: Removes duplicates
What it does: Returns unique values
Query: Unique departments
SELECT DISTINCT department
FROM employees;
15. LIKE
What it is: Pattern matching
What it does: Filters text patterns
Query: Names starting with A
SELECT *
FROM employees
WHERE name LIKE 'A%';
Double Tap ♥️ For MoreSELECT MAX(salary)
FROM employee
WHERE salary < (SELECT MAX(salary) FROM employee);
2️⃣ Get the top 3 products by revenue from sales table.
SELECT product_id, SUM(revenue) AS total_revenue
FROM sales
GROUP BY product_id
ORDER BY total_revenue DESC
LIMIT 3;
3️⃣ Use JOIN to combine customer and order data.
SELECT c.customer_name, o.order_id, o.order_date
FROM customers c
JOIN orders o ON c.customer_id = o.customer_id;
(That's an INNER JOIN—use LEFT JOIN to include all customers, even without orders.)
4️⃣ Difference between WHERE and HAVING?
⦁ WHERE filters rows before aggregation (e.g., on individual records).
⦁ HAVING filters rows after aggregation (used with GROUP BY on aggregates).
Example:
SELECT department, COUNT(*)
FROM employee
GROUP BY department
HAVING COUNT(*) > 5;
5️⃣ Explain INDEX and how it improves performance.
An INDEX is a data structure that improves the speed of data retrieval.
It works like a lookup table and reduces the need to scan every row in a table.
Especially useful for large datasets and on columns used in WHERE, JOIN, or ORDER BY—think 10x faster queries, but it slows inserts/updates a bit.
💬 Tap ❤️ for more!def reverse_string(s):
return s[::-1]
C++:
string reverseString(string s) {
reverse(s.begin(), s.end());
return s;
}
Java:
String reverseString(String s) {
return new StringBuilder(s).reverse().toString();
}
2️⃣ Check for Palindrome
Q: Check if a string is a palindrome.
Python:
def is_palindrome(s):
s = s.lower().replace(" ", "")
return s == s[::-1]
C++:
bool isPalindrome(string s) {
transform(s.begin(), s.end(), s.begin(), ::tolower);
s.erase(remove(s.begin(), s.end(), ' '), s.end());
return s == string(s.rbegin(), s.rend());
}
Java:
boolean isPalindrome(String s) {
s = s.toLowerCase().replaceAll(" ", "");
return s.equals(new StringBuilder(s).reverse().toString());
}
3️⃣ Count Vowels in a String
Q: Count number of vowels in a string.
Python:
def count_vowels(s):
return sum(1 for c in s.lower() if c in "aeiou")
C++:
int countVowels(string s) {
int count = 0;
for (char c: s) {
c = tolower(c);
if (string("aeiou").find(c)!= string::npos)
count++;
}
return count;
}
Java:
int countVowels(String s) {
int count = 0;
s = s.toLowerCase();
for (char c : s.toCharArray()) {
if ("aeiou".indexOf(c) != -1)
count++;
}
return count;
}
4️⃣ Find Factorial (Recursion)
Q: Find factorial using recursion.
Python:
def factorial(n):
return 1 if n <= 1 else n * factorial(n - 1)
C++:
int factorial(int n) {
return (n <= 1) ? 1 : n * factorial(n - 1);
}
Java:
int factorial(int n) {
return (n <= 1) ? 1 : n * factorial(n - 1);
}
5️⃣ Find Duplicate Elements in List/Array
Q: Print all duplicates from a list.
Python:
from collections import Counter
def find_duplicates(lst):
return [k for k, v in Counter(lst).items() if v > 1]
C++:
vector<int> findDuplicates(vector<int>& nums) {
unordered_map<int, int> freq;
vector<int> res;
for (int n : nums) freq[n]++;
for (auto& p : freq)
if (p.second > 1) res.push_back(p.first);
return res;
}
Java:
List<Integer> findDuplicates(int[] nums) {
Map<Integer, Integer> map = new HashMap<>();
List<Integer> result = new ArrayList<>();
for (int n : nums) map.put(n, map.getOrDefault(n, 0) + 1);
for (Map.Entry<Integer, Integer> entry : map.entrySet())
if (entry.getValue() > 1) result.add(entry.getKey());
return result;
}
Double Tap ♥️ For More