What is the result of evaluating the prefix expression '-+5*234'?
7
17
-7
-17
During the infix to postfix conversion of the expression 'A+B*C-D/E', which operator would be pushed onto the stack first?
/
How do stacks facilitate backtracking in algorithms?
By maintaining a record of visited states and enabling the algorithm to revert to previous states.
By optimizing the search space for the algorithm.
By storing the optimal solution found so far.
By providing a mechanism for parallel processing.
In a stack implemented using a linked list, where does the 'push' operation add the new element?
At a specific index in the linked list.
At the end of the linked list.
At the beginning of the linked list.
It depends on the data being inserted.
In maze-solving algorithms, how does the use of a stack differ between depth-first search (DFS) and breadth-first search (BFS)?
Both DFS and BFS use stacks identically; the difference lies in how they mark visited nodes.
DFS uses a stack only if the maze is solvable, while BFS always uses a queue.
DFS uses a stack to explore as deeply as possible before backtracking, while BFS uses a queue to explore all neighbors at a given level.
BFS uses a stack to prioritize unexplored paths, while DFS uses a queue to systematically explore all directions.
In postfix evaluation, what action is taken when an operand is encountered?
It is ignored.
It triggers the evaluation of operators on the stack.
It is pushed onto the stack.
It is immediately evaluated.
If you represent an arithmetic expression in postfix notation using a stack, what operation would you perform when encountering an operand (a number)?
Ignore the operand.
Pop the top two elements from the stack, perform the operation, and push the result back onto the stack.
Push the operand onto the stack.
Check if the stack is empty.
In a stack implemented using a singly linked list, which end of the list typically represents the top of the stack?
Head
Middle
It can be either the head or the tail, depending on the implementation.
Tail
What is the time complexity of the 'peek' operation in a well-implemented stack?
O(1)
O(n)
O(log n)
O(n log n)
Consider the scenario of undoing actions in a text editor. Which data structure would be most suitable for implementing an 'undo' feature?
Binary Tree
Queue
Linked List
Stack