Python Programming Coding Questions

Practice 70 most asked Python programming coding interview questions with solutions - Easy, Medium, and Hard levels.

1. Print "Hello World"

Easy 
Output: Hello World
print("Hello World")

2. Add two numbers

Easy 
Input: 10
       20
Output: 30
a = int(input())
b = int(input())
print(a + b)

3. Find maximum of two numbers

Easy 
Input: 10
       20
Output: 20
a = int(input())
b = int(input())
print(max(a, b))

4. Check if number is even or odd

Easy 
Input: 7
Output: Odd
n = int(input())
if n % 2 == 0:
    print("Even")
else:
    print("Odd")

5. Check if number is positive, negative or zero

Easy 
Input: -45
Output: Negative
n = int(input())
if n > 0:
    print("Positive")
elif n < 0:
    print("Negative")
else:
    print("Zero")

6. Find factorial of a number

Easy 
Input: 7
Output: 5040
n = int(input())
fact = 1
for i in range(1, n + 1):
    fact *= i
print(fact)

7. Print multiplication table

Easy 
Input: 7
Output: 7 x 1 = 7
7 x 2 = 14
7 x 3 = 21
7 x 4 = 28
7 x 5 = 35
7 x 6 = 42
7 x 7 = 49
7 x 8 = 56
7 x 9 = 63
7 x 10 = 70

n = int(input())
for i in range(1, 11):
    print(f"{n} x {i} = {n * i}")

8. Print Fibonacci series

Easy 
Input: 10
Output: 0 1 1 2 3 5 8 13 21 34
n = int(input())
a, b = 0, 1
for i in range(n):
    print(a, end=" ")
    a, b = b, a + b

9. Check if a number is prime

Easy 
Input: 29
Output: Prime
n = int(input())
if n <= 1:
    print("Not Prime")
else:
    for i in range(2, int(n**0.5) + 1):
        if n % i == 0:
            print("Not Prime")
            break
    else:
        print("Prime")

10. Sum of digits of a number

Easy 
Input: 456
Output: 15
n = int(input())
sum_digits = 0
while n > 0:
    sum_digits += n % 10
    n //= 10
print(sum_digits)

11. Reverse a number

Easy 
Input: 1234
Output: 4321
n = int(input())
rev = 0
while n > 0:
    rev = rev * 10 + n % 10
    n //= 10
print(rev)

12. Check palindrome number

Easy 
Input: 1221
Output: Palindrome
n = int(input())
temp = n
rev = 0
while n > 0:
    rev = rev * 10 + n % 10
    n //= 10
if temp == rev:
    print("Palindrome")
else:
    print("Not Palindrome")

13. Count number of digits

Easy 
Input: 90876
Output: 5
n = int(input())
count = 0
while n > 0:
    count += 1
    n //= 10
print(count)

14. Find sum of natural numbers

Easy 
Input: 10
Output: 55
n = int(input())
sum_n = n * (n + 1) // 2
print(sum_n)

15. Find largest of three numbers

Easy 
Input: 5
12
9
Output: 12
a = int(input())
b = int(input())
c = int(input())
print(max(a, b, c))

16. Swap two numbers

Easy 
Input: 3
7
Output: 7 3
a = int(input())
b = int(input())
a, b = b, a
print(a, b)

17. Find area of circle

Easy 
Input: 7
Output: 153.93804002589985
import math
r = float(input())
area = math.pi * r * r
print(area)

18. Convert Celsius to Fahrenheit

Easy 
Input: 25
Output: 77.0
celsius = float(input())
fahrenheit = (celsius * 9/5) + 32
print(fahrenheit)

19. Check leap year

Easy 
Input: 2024
Output: Leap Year
year = int(input())
if (year % 4 == 0 and year % 100 != 0) or (year % 400 == 0):
    print("Leap Year")
else:
    print("Not Leap Year")

20. Find simple interest

Easy 
Input: 1000
5
2
Output: 100.0
p = float(input())
r = float(input())
t = float(input())
si = (p * r * t) / 100
print(si)

21. Find compound interest

Easy 
Input: 1000
5
2
Output: 102.5
p = float(input())
r = float(input())
t = float(input())
ci = p * (1 + r/100)**t - p
print(ci)

22. Check Armstrong number

Easy 
Input: 153
Output: Armstrong
n = int(input())
temp = n
sum_arm = 0
digits = len(str(n))
while n > 0:
    sum_arm += (n % 10) ** digits
    n //= 10
if temp == sum_arm:
    print("Armstrong")
else:
    print("Not Armstrong")

23. Print all prime numbers in a range

Easy 
Input: 10
30
Output: 11 13 17 19 23 29 
start = int(input())
end = int(input())
for num in range(start, end + 1):
    if num > 1:
        for i in range(2, int(num**0.5) + 1):
            if num % i == 0:
                break
        else:
            print(num, end=" ")

24. Find GCD of two numbers

Easy 
Input: 24
36
Output: 12
import math
a = int(input())
b = int(input())
print(math.gcd(a, b))

25. Find LCM of two numbers

Easy 
Input: 12
18
Output: 36
import math
a = int(input())
b = int(input())
lcm = (a * b) // math.gcd(a, b)
print(lcm)

26. Check vowel or consonant

Easy 
Input: A
Output: Vowel
ch = input().lower()
if ch in 'aeiou':
    print("Vowel")
else:
    print("Consonant")

27. Count vowels in a string

Easy 
Input: education
Output: 5
s = input().lower()
count = sum(1 for ch in s if ch in 'aeiou')
print(count)

28. Reverse a string

Easy 
Input: Hello
Output: olleH
s = input()
print(s[::-1])

29. Check palindrome string

Easy 
Input: madam
Output: palindrome
s = input()
if s == s[::-1]:
    print("Palindrome")
else:
    print("Not Palindrome")

30. Find length of string without using len()

Easy 
Input: hello
Output: 5
s = input()
count = 0
for ch in s:
    count += 1
print(count)

31. Find sum of list elements

Medium 
Input: 1 2 3 4 5
Output: 15
arr = list(map(int, input().split()))
print(sum(arr))

32. Find largest element in list

Medium 
Input: 4 9 2 7 5
Output: 9
arr = list(map(int, input().split()))
print(max(arr))

33. Find smallest element in list

Medium 
Input: 4 9 2 7 5
Output: 2
arr = list(map(int, input().split()))
print(min(arr))

34. Sort a list in ascending order

Medium 
Input: 5 1 4 2 3
Output: [1, 2, 3, 4, 5]
arr = list(map(int, input().split()))
arr.sort()
print(arr)

35. Linear search in list

Medium 
Input: 10 20 30 40 50
30
Output: Found at index 2
arr = list(map(int, input().split()))
key = int(input())
if key in arr:
    print(f"Found at index {arr.index(key)}")
else:
    print("Not Found")

36. Binary search in sorted list

Medium 
Input: 1 3 5 7 9 11
7
Output: Found at index 3
arr = list(map(int, input().split()))
key = int(input())
left, right = 0, len(arr) - 1
while left <= right:
    mid = (left + right) // 2
    if arr[mid] == key:
        print(f"Found at index {mid}")
        break
    elif arr[mid] < key:
        left = mid + 1
    else:
        right = mid - 1
else:
    print("Not Found")

37. Remove duplicates from list

Medium 
Input: 1 2 2 3 4 4 5
Output: [1, 2, 3, 4, 5]
arr = list(map(int, input().split()))
unique = list(set(arr))
print(unique)

38. Find frequency of elements in list

Medium 
Input: 1 2 2 3 3 3 4
Output: {1: 1, 2: 2, 3: 3, 4: 1}
arr = list(map(int, input().split()))
freq = {}
for num in arr:
    freq[num] = freq.get(num, 0) + 1
print(freq)

39. Merge two lists

Medium 
Input: 1 2 3
4 5 6
Output: [1, 2, 3, 4, 5, 6]
arr1 = list(map(int, input().split()))
arr2 = list(map(int, input().split()))
merged = arr1 + arr2
print(merged)

40. Find second largest element

Medium 
Input: 10 20 20 30 40
Output: 30
arr = list(map(int, input().split()))
arr = list(set(arr))
arr.sort()
if len(arr) >= 2:
    print(arr[-2])
else:
    print("Not enough elements")

41. Rotate list by k positions

Medium 
Input: 1 2 3 4 5
2
Output: [3, 4, 5, 1, 2]
arr = list(map(int, input().split()))
k = int(input())
k = k % len(arr)
rotated = arr[k:] + arr[:k]
print(rotated)

42. Find missing number in list (1 to n)

Medium 
Input: 1 2 4 5 6
Output: 3
arr = list(map(int, input().split()))
n = len(arr) + 1
expected_sum = n * (n + 1) // 2
actual_sum = sum(arr)
print(expected_sum - actual_sum)

43. Check if list is sorted

Medium 
Input: 1 2 3 4 5
Output: Sorted
arr = list(map(int, input().split()))
if arr == sorted(arr):
    print("Sorted")
else:
    print("Not Sorted")

44. Find pairs with given sum

Medium 
Input: 1 2 3 4 5
5
Output: [(1, 4), (2, 3)]
arr = list(map(int, input().split()))
target = int(input())
pairs = []
for i in range(len(arr)):
    for j in range(i + 1, len(arr)):
        if arr[i] + arr[j] == target:
            pairs.append((arr[i], arr[j]))
print(pairs)

45. Count words in a string

Medium 
Input: Hello world from Python
Output: 4
s = input()
words = s.split()
print(len(words))

46. Remove spaces from string

Medium 
Input: Hello world Python
Output: HelloworldPython
s = input()
result = s.replace(" ", "")
print(result)

47. Check if two strings are anagrams

Medium 
Input: listen
silent
Output: Anagrams
s1 = input()
s2 = input()
if sorted(s1) == sorted(s2):
    print("Anagrams")
else:
    print("Not Anagrams")

48. Find first non-repeating character

Medium 
Input: swiss
Output: w
s = input()
for ch in s:
    if s.count(ch) == 1:
        print(ch)
        break
else:
    print("None")

49. Count uppercase and lowercase letters

Medium 
Input: Hello World
Output: Uppercase: 2, Lowercase: 8
s = input()
upper = sum(1 for ch in s if ch.isupper())
lower = sum(1 for ch in s if ch.islower())
print(f"Uppercase: {upper}, Lowercase: {lower}")

50. Toggle case of string

Medium 
Input: Hello World
Output: hELLO wORLD
s = input()
print(s.swapcase())

51. Find all substrings of a string

Medium 
Input: abc
Output: ['a', 'ab', 'abc', 'b', 'bc', 'c']
s = input()
substrings = []
for i in range(len(s)):
    for j in range(i + 1, len(s) + 1):
        substrings.append(s[i:j])
print(substrings)

52. Replace substring in string

Medium 
Input: I like apples
apples
oranges
Output: I like oranges
s = input()
old = input()
new = input()
print(s.replace(old, new))

53. Check if string contains only digits

Medium 
Input: 12345
Output: 12345
s = input()
if s.isdigit():
    print("Only digits")
else:
    print("Not only digits")

54. Find longest word in string

Medium 
Input: I love programming in Python
Output: programming
s = input()
words = s.split()
longest = max(words, key=len)
print(longest)

55. Remove punctuation from string

Medium 
Input: Hello, world! Welcome to Python.
Output: Hello world Welcome to Python
import string
s = input()
result = s.translate(str.maketrans('', '', string.punctuation))
print(result)

56. Matrix addition

Hard 
Input: 2
3
1 2 3
4 5 6
6 5 4
3 2 1
Output: [7, 7, 7]
[7, 7, 7]

rows = int(input())
cols = int(input())
mat1 = [list(map(int, input().split())) for _ in range(rows)]
mat2 = [list(map(int, input().split())) for _ in range(rows)]
result = [[mat1[i][j] + mat2[i][j] for j in range(cols)] for i in range(rows)]
for row in result:
    print(row)

57. Matrix multiplication

Hard 
Input: 2 3
1 2 3
4 5 6
3 2
7 8
9 10
11 12
Output: [58, 64]
[139, 154]

r1, c1 = map(int, input().split())
mat1 = [list(map(int, input().split())) for _ in range(r1)]
r2, c2 = map(int, input().split())
mat2 = [list(map(int, input().split())) for _ in range(r2)]
result = [[sum(mat1[i][k] * mat2[k][j] for k in range(c1)) 
           for j in range(c2)] for i in range(r1)]
for row in result:
    print(row)

58. Transpose of matrix

Hard 
Input: 2
3
1 2 3
4 5 6
Output: [1, 4]
[2, 5]
[3, 6]

rows = int(input())
cols = int(input())
mat = [list(map(int, input().split())) for _ in range(rows)]
transpose = [[mat[j][i] for j in range(rows)] for i in range(cols)]
for row in transpose:
    print(row)

59. Generate Pascal's triangle

Hard 
Input: 5
Output: [1]
[1, 1]
[1, 2, 1]
[1, 3, 3, 1]
[1, 4, 6, 4, 1]

n = int(input())
triangle = []
for i in range(n):
    row = [1] * (i + 1)
    for j in range(1, i):
        row[j] = triangle[i-1][j-1] + triangle[i-1][j]
    triangle.append(row)
    print(row)

60. Find all permutations of string

Hard 
Input: abc
Output: ['abc', 'acb', 'bac', 'bca', 'cab', 'cba']
from itertools import permutations
s = input()
perms = [''.join(p) for p in permutations(s)]
print(perms)

61. Find all combinations of list

Hard 
Input: 1 2 3 4
2
Output: [(1, 2), (1, 3), (1, 4), (2, 3), (2, 4), (3, 4)]
from itertools import combinations
arr = list(map(int, input().split()))
r = int(input())
combs = list(combinations(arr, r))
print(combs)

62. Implement stack using list

Hard 
Output: 20
class Stack:
    def __init__(self):
        self.items = []
    
    def push(self, item):
        self.items.append(item)
    
    def pop(self):
        return self.items.pop() if self.items else None
    
    def peek(self):
        return self.items[-1] if self.items else None
    
    def is_empty(self):
        return len(self.items) == 0

s = Stack()
s.push(10)
s.push(20)
print(s.pop())

63. Implement queue using list

Hard 
Output: 10
from collections import deque

class Queue:
    def __init__(self):
        self.items = deque()
    
    def enqueue(self, item):
        self.items.append(item)
    
    def dequeue(self):
        return self.items.popleft() if self.items else None
    
    def is_empty(self):
        return len(self.items) == 0

q = Queue()
q.enqueue(10)
q.enqueue(20)
print(q.dequeue())

64. Find longest common subsequence

Hard 
Input: AGGTAB
GXTXAYB
Output: 4
def lcs(s1, s2):
    m, n = len(s1), len(s2)
    dp = [[0] * (n + 1) for _ in range(m + 1)]
    for i in range(1, m + 1):
        for j in range(1, n + 1):
            if s1[i-1] == s2[j-1]:
                dp[i][j] = dp[i-1][j-1] + 1
            else:
                dp[i][j] = max(dp[i-1][j], dp[i][j-1])
    return dp[m][n]

s1 = input()
s2 = input()
print(lcs(s1, s2))

65. Solve Tower of Hanoi

Hard 
Input: 2
Output: Move disk 1 from A to B
Move disk 2 from A to C
Move disk 1 from B to C

def tower_of_hanoi(n, source, auxiliary, destination):
    if n == 1:
        print(f"Move disk 1 from {source} to {destination}")
        return
    tower_of_hanoi(n-1, source, destination, auxiliary)
    print(f"Move disk {n} from {source} to {destination}")
    tower_of_hanoi(n-1, auxiliary, source, destination)

n = int(input())
tower_of_hanoi(n, 'A', 'B', 'C')

66. Find nth Fibonacci using memoization

Hard 
Input: 7
Output: 13
def fibonacci(n, memo={}):
    if n in memo:
        return memo[n]
    if n <= 1:
        return n
    memo[n] = fibonacci(n-1, memo) + fibonacci(n-2, memo)
    return memo[n]

n = int(input())
print(fibonacci(n))

67. Merge two sorted lists

Hard 
Input: 1 3 5
2 4 6
Output: [1, 2, 3, 4, 5, 6]

def merge_sorted(arr1, arr2):
    result = []
    i, j = 0, 0
    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
    result.extend(arr1[i:])
    result.extend(arr2[j:])
    return result

arr1 = list(map(int, input().split()))
arr2 = list(map(int, input().split()))
print(merge_sorted(arr1, arr2))

68. Quick Sort implementation

Hard 
Input: 5 3 8 4 2
Output: [2, 3, 4, 5, 8]
def quick_sort(arr):
    if len(arr) <= 1:
        return arr
    pivot = arr[len(arr) // 2]
    left = [x for x in arr if x < pivot]
    middle = [x for x in arr if x == pivot]
    right = [x for x in arr if x > pivot]
    return quick_sort(left) + middle + quick_sort(right)

arr = list(map(int, input().split()))
print(quick_sort(arr))

69. Merge Sort implementation

Hard 
Input: 9 4 7 1 5
Output: [1, 4, 5, 7, 9]
def merge_sort(arr):
    if len(arr) <= 1:
        return arr
    mid = len(arr) // 2
    left = merge_sort(arr[:mid])
    right = merge_sort(arr[mid:])
    return merge(left, right)

def merge(left, right):
    result = []
    i = j = 0
    while i < len(left) and j < len(right):
        if left[i] < right[j]:
            result.append(left[i])
            i += 1
        else:
            result.append(right[j])
            j += 1
    result.extend(left[i:])
    result.extend(right[j:])
    return result

arr = list(map(int, input().split()))
print(merge_sort(arr))

70. Find all prime factors of a number

Hard 
Input: 60
Output: [2, 2, 3, 5]
def prime_factors(n):
    factors = []
    d = 2
    while d * d <= n:
        while n % d == 0:
            factors.append(d)
            n //= d
        d += 1
    if n > 1:
        factors.append(n)
    return factors

n = int(input())
print(prime_factors(n))