ITPEC FE Subject B October 2025 Question 11

Modified bubble sort with early termination: fill in the while-loop condition blanks.

The function quickBubble is an optimized bubble sort that stops early when no swaps occur during a pass. The while-loop needs two conditions to work correctly:

• •Blank A — `maxIdx > 0`: The inner for loop runs i from 1 to maxIdx, comparing arraySorted[i] with arraySorted[i + 1]. For at least one comparison to happen, maxIdx must be ≥ 1, i.e. maxIdx > 0. After each pass, maxIdx decreases by 1 (the largest unsorted element "bubbles up" to position maxIdx + 1). Using maxIdx > 1 would skip the final single-pair pass when maxIdx = 1.

• •Blank B — `exchange = true`: Before each pass, exchange is reset to false. If any swap occurs, it becomes true. The while-loop should continue as long as swaps happened — meaning the array may not yet be sorted. If no swaps occurred (exchange = false), the array is already sorted and the loop exits early.

Why not others:
- b) `maxIdx > 0` and `exchange = false` — would continue only when no swaps occurred, which is the opposite of the intended logic
- c) `maxIdx > 1` and `exchange = true` — maxIdx > 1 would prevent the last necessary pass when only two unsorted elements remain (maxIdx = 1)
- d) `maxIdx > 1` and `exchange = false` — combines both wrong conditions

Key rule: In early-termination bubble sort, the flag tracks whether a swap happened. The loop continues while exchange = true (swaps occurred → array might not be sorted yet). The boundary condition maxIdx > 0 ensures every needed pass executes, including the final single-comparison pass.

AI-generated — may contain errors