Daily Coding Quiz: Monday, 2 November 2026

All 10 coding questions with answers and explanations. 0 players took part.

1. Which of these is a stable sorting algorithm by default?

   DSA · easy · 100% of players got it right

   1. Quick sort
   2. Heap sort
   3. Merge sort
   4. Selection sort

   Answer: C. Merge sort

   Explanation: Merge sort keeps equal elements in their original order (take from the left half on ties). Standard quick, heap and selection sort do not.

2. What is printed?

   Python · easy · 0% of players got it right

   s = "Python"
   print(s[-1], s[::-1])

   1. n nohtyP
   2. P nohtyP
   3. n Python
   4. nohtyP n

   Answer: A. n nohtyP

   Explanation: s[-1] is the last character; a step of −1 walks the string backwards, reversing it.

3. Which keyword creates a generator function?

   Python · easy · 100% of players got it right

   1. return
   2. yield
   3. async
   4. lambda

   Answer: B. yield

   Explanation: A function containing yield returns a generator: it produces values lazily, pausing at each yield.

4. Floyd’s “tortoise and hare” algorithm is mainly used to:

   DSA · medium · 0% of players got it right

   1. Sort a linked list
   2. Detect a cycle in a linked list
   3. Reverse a linked list
   4. Merge two sorted lists

   Answer: B. Detect a cycle in a linked list

   Explanation: One pointer moves 1 step, the other 2. If there is a cycle the fast pointer eventually meets the slow one; if not, it reaches the end.

5. What is printed?

   Python · medium · 0% of players got it right

   a = [1, 2, 3]
   b = a
   b += [4]
   print(a)

   1. [1, 2, 3]
   2. [1, 2, 3, 4]
   3. [4]
   4. An error

   Answer: B. [1, 2, 3, 4]

   Explanation: b = a makes both names point to the same list, and += on a list extends it in place, so a sees the change.

6. What is printed?

   Python · medium · 0% of players got it right

   from collections import Counter
   c = Counter("mississippi")
   print(c.most_common(2))

   1. [('i', 4), ('s', 4)]
   2. [('s', 4), ('i', 4)]
   3. [('i', 4), ('p', 2)]
   4. [('m', 1), ('i', 4)]

   Answer: A. [('i', 4), ('s', 4)]

   Explanation: i and s both appear 4 times. Ties keep the order in which elements were first seen, and i (index 1) appears before s (index 2).

7. What is printed?

   Python · medium · 0% of players got it right

   a = [[0] * 2] * 2
   a[0][0] = 1
   print(a)

   1. [[1, 0], [0, 0]]
   2. [[1, 0], [1, 0]]
   3. [[1, 1], [0, 0]]
   4. An error

   Answer: B. [[1, 0], [1, 0]]

   Explanation: * 2 on the outer list copies the reference, so both rows are the same list object. Use [[0] * 2 for _ in range(2)] for independent rows.

8. What is the time complexity of the classic dynamic-programming solution to the Longest Common Subsequence of strings of length m and n?

   DSA · hard · 0% of players got it right

   1. O(m + n)
   2. O(m · n)
   3. O(2^(m+n))
   4. O((m + n) log(m + n))

   Answer: B. O(m · n)

   Explanation: The DP table has (m+1)(n+1) cells and each is filled in O(1) from its neighbours.

9. What is printed?

   Python · hard · 0% of players got it right

   def deco(fn):
       def wrap(*a):
           return fn(*a) * 2
       return wrap
   
   @deco
   @deco
   def three():
       return 3
   
   print(three())

   1. 6
   2. 9
   3. 12
   4. 3

   Answer: C. 12

   Explanation: Stacked decorators apply bottom-up: three = deco(deco(three)). The inner wrapper doubles 3 to 6, the outer doubles that to 12.

10. What is printed?

    Python · hard · 0% of players got it right

    x = [1, 2, 3]
    y = x[:]
    z = x
    x.append(4)
    print(len(y), len(z), y is x, z is x)

    1. 3 4 False True
    2. 4 4 False True
    3. 3 3 True True
    4. 4 4 True True

    Answer: A. 3 4 False True

    Explanation: x[:] makes a shallow copy (a new list), so y keeps 3 items. z is just another name for x.

Top 10

1. Sriharini Kalidas: 24 points (2/10)

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