Stacks

Question 1

Hint of Stack

Answer 1

Ins and outs

Question 2

is it better than array?

Answer 2

It is favorable to store data in a stack than array

Question 3

What does stack use?

Answer 3

LIFO- Last in First out

Question 4

Operations-

Answer 4

empty()
size() 
top()
push(a)
pop()

Question 5

empty()

Answer 5

empty() – Returns whether the stack is empty – Time Complexity: O(1)

Question 6

size()

Answer 6

size() – Returns the size of the stack – Time Complexity: O(1)

Question 7

top()

Answer 7

top() – Returns the topmost element of the stack – Time Complexity: O(1)

Question 8

pop()

Answer 8

pop() – Deletes the topmost element of the stack – Time Complexity: O(1)

Question 9

append()

Answer 9

append(a) – Inserts the element ‘a’ at the top of the stack – Time Complexity: O(1)

Question 10

Does stack offer constant time access to the ith item?

Answer 10

Stack does not offer constant time access to the ith item.

Question 11

Constant time access-

Answer 11

only append() and pop() has the constant time access because it doesn’t shift elements around

Question 12

Is stack linked list?

Answer 12

Stack can be implemented as linked list if the items are added and removed from the same side.

Question 13

Stack in Recursive algorithms

Answer 13

Append temporary data onto a stack as we recurse, but remove as we bcktrack

Question 14

Can stack help recursive algorithm to iterate?

Answer 14

It can be use to implement iteratively.