DSA - Infosys Power Programmer

What is the time complexity of computing prefix sum for an array of size n?

• O(1)
• O(n^2)
• O(n)
• O(log n)

Which of the following is the prefix sum of array [2, 4, 6]?

• [2, 6, 12]
• [2, 4, 6]
• [2, 8, 14]
• [2, 6, 10]

How to get the sum of subarray [i..j] using prefix sum array?

• prefix[j] - prefix[i]
• prefix[j]-prefix[i+1]
• prefix[j+1]-prefix[i]
• prefix[j+1]-prefix[i+1]

What is the prefix sum array of [1, -1, 3, 2]?

• [1, 0, 3, 5]
• [1, 1, 4, 6]
• [1, -1, 2, 4]
• [1, 0, 2, 3]

Which operation becomes efficient using prefix sums?

• Sorting
• Searching
• Subarray sum
• Rotating array

In prefix sum, what is prefix[0] typically initialized to?

• 0
• 1
• First element
• None of the above

If prefix sum array is [3, 7, 12, 20], what is the original array?

• [3, 4, 5, 8]
• [3, 7, 12, 20]
• [3, 10, 5, 8]
• [3, 7, 12, 32]

For array A = [5, 2, 1, 3], what is prefix sum at index 2?

• 8
• 6
• 7
• 3

What is the sum of elements from index 1 to 3 in A = [1, 2, 3, 4], using prefix sum?

• 9
• 5
• 6
• 7

Which data structure is best suited for prefix sum queries with frequent updates?

• Array
• Stack
• Binary Indexed Tree
• Queue