Computer Science – 19.1 Algorithms | e-Consult
19.1 Algorithms (1 questions)
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A stack is an ADT that follows the Last-In, First-Out (LIFO) principle. Its core operations are:
- Push(element): Adds an element to the top of the stack.
- Pop(): Removes the element from the top of the stack.
- Peek(): Returns the element at the top of the stack without removing it.
- IsEmpty(): Checks if the stack is empty.
A stack can be implemented using an array. The array acts as the underlying storage for the stack elements. A pointer (or index) is used to keep track of the top of the stack. When an element is pushed, it's added to the top of the array, and the top pointer is incremented. When an element is popped, the element at the top of the array is removed, and the top pointer is decremented.
Advantages of array implementation:
- Simple to implement: Array-based stacks are relatively straightforward to implement.
- Efficient for small stacks: Push and pop operations are typically O(1) time complexity.
Disadvantages of array implementation:
- Fixed size: Arrays have a fixed size, which can lead to overflow if the stack grows too large. This requires resizing, which can be time-consuming.
- Potential for wasted space: If the stack is not fully utilized, some space in the array may be wasted.