Python Coding Interview Questions and Answers

Ques 1. Write a function to reverse a string.

def reverse_string(input_str):

return input_str[::-1]

Example:

reverse_string('hello')  # Output: 'olleh'

Ques 2. Implement a function to check if a string is a palindrome.

def is_palindrome(input_str):

return input_str == input_str[::-1]

Example:

is_palindrome('radar')  # Output: True

Ques 3. Write a Python function to check if a given year is a leap year.

def is_leap_year(year):

return (year % 4 == 0 and year % 100 != 0) or (year % 400 == 0)

Example:

is_leap_year(2024)  # Output: True

Ques 4. Implement a function to find the maximum element in a list.

def find_max_element(lst):

return max(lst)

Example:

find_max_element([3, 7, 2, 8, 5])  # Output: 8

Ques 5. Write a Python program to count the occurrences of each element in a list.

from collections import Counter

def count_occurrences(lst):

  return Counter(lst)

Example:

Ques 6. Create a function to check if a given string is an anagram of another string.

def is_anagram(str1, str2):

  return sorted(str1) == sorted(str2)

Example:

Ques 7. Implement a function to remove duplicates from a list.

def remove_duplicates(lst):

  return list(set(lst))

Example:

Ques 8. Write a Python program to find the factorial of a number.

def factorial(n):

  return 1 if n == 0 else n * factorial(n-1)

Example:

Ques 9. Implement a function to check if a number is prime.

def is_prime(num):

  if num < 2:

  return False

  for i in range(2, int(num**0.5) + 1):

    if num % i == 0:

      return False

   return True

Example:

Ques 10. Create a Python class for a basic stack implementation.

class Stack:

  def __init__(self):

    self.items = []

 

  def push(self, item):

    self.items.append(item)

 

  def pop(self):

    return self.items.pop()

 

  def is_empty(self):

    return len(self.items) == 0

Example:

Ques 11. Write a Python program to find the nth Fibonacci number.

def fibonacci(n):

  if n <= 1:

    return n

  else:

    return fibonacci(n-1) + fibonacci(n-2)

Example:

Ques 12. Write a Python program to find the length of the longest increasing subsequence in an array.

def longest_increasing_subsequence(arr):

  n = len(arr)\n lis = [1]*n

  for i in range(1, n):

    for j in range(0, i):

      if arr[i] > arr[j] and lis[i] < lis[j] + 1:

        lis[i] = lis[j] + 1

          return max(lis)

Example:

Ques 13. Create a Python generator function to generate the power set of a given set.

def power_set(input_set):

  n = len(input_set)

  for i in range(1 << n):

    subset = [input_set[j]

      for j in range(n):

        if (i & (1 << j)) > 0]

          yield subset

Example:

Ques 14. Write a Python function to implement the binary search algorithm.

def binary_search(arr, target):

  low, high = 0, len(arr) - 1

  while low <= high:

    mid = (low + high) // 2

    if arr[mid] == target:

      return mid

    elif arr[mid] < target:

      low = mid + 1

    else:

      high = mid - 1

    return -1

Example:

Ques 15. Implement a function to find the intersection of two lists.

def intersection(list1, list2):

  return list(set(list1) & set(list2))

Example:

Ques 16. Write a Python program to perform matrix multiplication.

import numpy as np

matrix1 = np.array([[1, 2], [3, 4]])

matrix2 = np.array([[5, 6], [7, 8]])

result = np.dot(matrix1, matrix2)

Example:

Ques 17. Create a generator function to generate Fibonacci numbers.

def fibonacci_generator():

  a, b = 0, 1

  while True:

    yield a

    a, b = b, a + b

Example:

Ques 18. Implement a depth-first search (DFS) algorithm for a graph.

def dfs(graph, node, visited):

  if node not in visited:

    print(node)

    visited.add(node)

    for neighbor in graph[node]:

      dfs(graph, neighbor, visited)

Example:

Ques 19. Implement a function to check if a binary tree is balanced.

class TreeNode:
 def __init__(self, value):
 self.value = value
 self.left = None
 self.right = None

def is_balanced(root):
 if root is None:
 return True
 left_height = height(root.left)
 right_height = height(root.right)
 return abs(left_height - right_height) <= 1 and is_balanced(root.left) and is_balanced(root.right)

def height(node):
 if node is None:
 return 0
 return max(height(node.left), height(node.right)) + 1

Example:

Ques 20. Write a Python program to implement a simple LRU (Least Recently Used) cache.

from collections import OrderedDict

class LRUCache:
 def __init__(self, capacity):
 self.cache = OrderedDict()
 self.capacity = capacity

 def get(self, key):
 if key in self.cache:
 self.cache.move_to_end(key)
 return self.cache[key]
 return -1

 def put(self, key, value):
 if len(self.cache) >= self.capacity:
 self.cache.popitem(last=False)
 self.cache[key] = value
 self.cache.move_to_end(key)

Example: