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
Show more๐ Analytical overview of Telegram channel Coding Interview Resources
Channel Coding Interview Resources (@crackingthecodinginterview) in the English language segment is an active participant. Currently, the community unites 52 122 subscribers, ranking 2 563 in the Technologies & Applications category and 7 263 in the India region.
๐ Audience metrics and dynamics
Since its creation on ะฝะตะฒัะดะพะผะพ, the project has demonstrated rapid growth, gathering an audience of 52 122 subscribers.
According to the latest data from 05 June, 2026, the channel demonstrates stable activity. Although there has been a change in the number of participants by 194 over the last 30 days and by 11 over the last 24 hours, overall reach remains high.
- Verification status: Not verified
- Engagement rate (ER): The average audience engagement rate is 1.93%. Within the first 24 hours after publication, content typically collects 0.84% reactions from the total number of subscribers.
- Post reach: On average, each post receives 1 005 views. Within the first day, a publication typically gains 437 views.
- Reactions and interaction: The audience actively supports content: the average number of reactions per post is 2.
- Thematic interests: Content is focused on key topics such as array, stack, algorithm, programming, sort.
๐ Description and content policy
The author describes the resource as a platform for expressing subjective opinions:
โThis channel contains the free resources and solution of coding problems which are usually asked in the interviews.
Managed by: @love_dataโ
Thanks to the high frequency of updates (latest data received on 07 June, 2026), the channel maintains relevance and a high level of publication reach. Analytics show that the audience actively interacts with content, making it an important point of influence in the Technologies & Applications category.
SELECT MAX(salary)
FROM employee
WHERE salary < (SELECT MAX(salary) FROM employee);
2๏ธโฃ 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;
3๏ธโฃ 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 JOINโuse LEFT JOIN to include all customers, even without orders.)
4๏ธโฃ Difference between WHERE and HAVING?
โฆ WHERE filters rows before aggregation (e.g., on individual records).
โฆ HAVING filters rows after aggregation (used with GROUP BY on aggregates).
Example:
SELECT department, COUNT(*)
FROM employee
GROUP BY department
HAVING COUNT(*) > 5;
5๏ธโฃ 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 BYโthink 10x faster queries, but it slows inserts/updates a bit.
๐ฌ Tap โค๏ธ 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();
}
2๏ธโฃ 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());
}
3๏ธโฃ 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;
}
4๏ธโฃ 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);
}
5๏ธโฃ 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 โฅ๏ธ For More
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