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 more📈 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 52 248 subscribers, ranking 2 474 in the Technologies & Applications category and 6 815 in the India region.
📊 Audience metrics and dynamics
Since its creation on невідомо, the project has demonstrated rapid growth, gathering an audience of 52 248 subscribers.
According to the latest data from 26 August, 2026, the channel demonstrates stable activity. Although there has been a change in the number of participants by 31 over the last 30 days and by -3 over the last 24 hours, overall reach remains high.
- Verification status: Not verified
- Engagement rate (ER): The average audience engagement rate is 1.85%. Within the first 24 hours after publication, content typically collects 0.76% reactions from the total number of subscribers.
- Post reach: On average, each post receives 966 views. Within the first day, a publication typically gains 398 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.
📝 Description and content policy
The author describes the resource as a platform for expressing subjective opinions:
“This channel contains the free resources and solution of coding problems which are usually asked in the interviews.
Managed by: @love_data”
Thanks to the high frequency of updates (latest data received on 27 August, 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.
s = "hello"
# Method 1: Slicing
reversed_s = s[::-1] # "olleh"
# Method 2: Two Pointers (In-place logic)
chars = list(s)
left, right = 0, len(chars) - 1
while left < right:
chars[left], chars[right] = chars[right], chars[left]
left += 1
right -= 1
reversed_s = ''.join(chars)
52. How do you check if a string is a palindrome?def is_palindrome(s):
# Clean string: lowercase and remove spaces
s = s.lower().replace(" ", "")
# Method 1: Slicing
return s == s[::-1]
# Method 2: Two Pointers
left, right = 0, len(s) - 1
while left < right:
if s[left] != s[right]:
return False
left += 1
right -= 1
return True
53. How do you find duplicates in an array?arr = [1, 2, 2, 3]
seen = set()
dups = set()
for num in arr:
if num in seen:
dups.add(num)
seen.add(num)
print(list(dups)) # Output: [2]
54. How do you find the missing number in a range from 1 to n?arr = [1, 2, 4] # Missing 3
n = len(arr) + 1 # Should be 4 elements total
expected_sum = n * (n + 1) // 2
actual_sum = sum(arr)
missing_number = expected_sum - actual_sum # 3
55. How do you merge two sorted arrays?arr1, arr2 = [1, 3], [2, 4]
i, j = 0, 0
result = []
while i < len(arr1) and j < len(arr2):
if arr1[i] < arr2[j]:
result.append(arr1[i])
i += 1
else:
result.append(arr2[j])
j += 1
# Append remaining elements
result.extend(arr1[i:])
result.extend(arr2[j:])
56. How do you find the nth Fibonacci number?def fib(n):
if n <= 1:
return n
a, b = 0, 1
for _ in range(2, n + 1):
a, b = b, a + b
return b
print(fib(6)) # Output: 8
57. How do you compute factorial? (Recursion vs Memoization)# Simple Recursion
def fact(n):
if n <= 1: return 1
return n * fact(n - 1)
# Recursive with Memoization (Optimization)
memo = {}
def fact_memo(n):
if n in memo: return memo[n]
if n <= 1: return 1
memo[n] = n * fact_memo(n - 1)
return memo[n]
print(fact(5)) # Output: 120
58. How do you remove duplicates from a sorted array in-place?arr = [1, 1, 2, 2, 3]
if not arr: return 0
slow = 0
for fast in range(1, len(arr)):
if arr[fast] != arr[slow]:
slow += 1
arr[slow] = arr[fast]
# Resulting array up to 'slow + 1' index
print(arr[:slow + 1]) # Output: [1, 2, 3]
59. How do you solve the Two Sum problem?nums, target = [2, 7, 11, 15], 9
mapping = {}
for i, num in enumerate(nums):
complement = target - num
if complement in mapping:
print([mapping[complement], i]) # Output: [0, 1]
mapping[num] = i
60. Interview tip you must remember
- Code Cleanly: Use meaningful variable names (e.g., current_sum instead of s).
- Test Immediately: Verbally walk through your code with a small test case before the interviewer asks you to.
- Discuss Optimization: Always mention Time and Space Complexity. Say: *"This is O(n) time and O(n) space. We could optimize space by..."*
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Double Tap ❤️ For Part 7<article>, <section>, <nav>, <header>). Improves accessibility and SEO.
4. What is the DOM
Document Object Model — a tree-like structure representing HTML elements. JavaScript can manipulate it to update content dynamically.
5. What is the difference between GET and POST methods
• GET: Sends data via URL, used for fetching
• POST: Sends data in body, used for submitting forms securely
6. What is the box model in CSS
Every HTML element is a box:
Content → Padding → Border → Margin
7. What is the difference between relative, absolute, and fixed positioning in CSS
• Relative: Moves element relative to its normal position
• Absolute: Positions element relative to nearest positioned ancestor
• Fixed: Stays in place even when scrolling
8. What is the difference between == and === in JavaScript
• ==: Compares values with type coercion
• ===: Strict comparison (value and type)
9. What is event bubbling in JavaScript
Events propagate from child to parent elements. Can be controlled using stopPropagation().
10. What is the difference between localStorage and sessionStorage
• localStorage: Persistent across sessions
• sessionStorage: Cleared when tab is closed
11. What is a RESTful API
An architectural style for designing networked applications using HTTP methods (GET, POST, PUT, DELETE) and stateless communication.
12. What is the difference between frontend and backend development
• Frontend: Client-side (UI/UX, HTML/CSS/JS)
• Backend: Server-side (databases, APIs, authentication)
13. What are common HTTP status codes
• 200 OK
• 404 Not Found
• 500 Internal Server Error
• 403 Forbidden
• 301 Moved Permanently
14. What is a promise in JavaScript
An object representing the eventual completion or failure of an async operation.
States: pending, fulfilled, rejected
15. What is the difference between synchronous and asynchronous code
• Synchronous: Executes line by line
• Asynchronous: Executes independently, doesn’t block the main thread
16. What is a CSS preprocessor
Tools like SASS or LESS that add features to CSS (variables, nesting, mixins) and compile into standard CSS.
17. What is the role of frameworks like React, Angular, or Vue
They simplify building complex UIs with reusable components, state management, and routing.
18. What is the difference between SQL and NoSQL databases
• SQL: Structured, relational (e.g., MySQL)
• NoSQL: Flexible schema, document-based (e.g., MongoDB)
19. What is version control and why is Git important
Version control tracks changes in code. Git allows collaboration, branching, and rollback. Platforms: GitHub, GitLab, Bitbucket
20. How do you optimize website performance
• Minify CSS/JS
• Use lazy loading
• Compress images
• Use CDN
• Reduce HTTP requests
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