ITPEC IP April 2026 Question 5
ITPEC IP April 2026 — Question 5 of 100
A stack containing 2 above 1 — trace every operation from the top and preserve the untouched lower boxes.
Write the stack from bottom to top. It starts as [1, 2, 2, 3, 4].
- •Operation 1 removes 4 and 3, then pushes 7:
[1, 2, 2, 7] - •Operation 2 pushes 3:
[1, 2, 2, 7, 3] - •Operation 3 removes
3, 7, 2; their average is 4, so[1, 2, 4] - •Operation 4 removes 4 and 2;
|4 − 2| = 2, so[1, 2]
Answer (b)
Why not others:
- (a) drops the bottom box and incorrectly produces 0
- (c) leaves the original top value 4, although it was consumed in operation 1
- (d) leaves too many boxes; every multi-box operation replaces its inputs with one result
Key rule: For a stack, only the top items are removed. After each operation, record the whole stack before continuing.
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