What is the time complexity of finding the minimum element in a stack that suppo
Practice Questions
Q1
What is the time complexity of finding the minimum element in a stack that supports this operation?
O(1)
O(n)
O(log n)
O(n^2)
Questions & Step-by-Step Solutions
What is the time complexity of finding the minimum element in a stack that supports this operation?
Step 1: Understand what a stack is. A stack is a data structure that follows the Last In First Out (LIFO) principle, meaning the last element added is the first one to be removed.
Step 2: Know that we want to find the minimum element in this stack quickly.
Step 3: Realize that if we only use one stack, we would have to look through all the elements to find the minimum, which takes time proportional to the number of elements, O(n).
Step 4: To improve this, we can use a second stack to keep track of the minimum elements.
Step 5: Every time we add an element to the main stack, we also check if it is smaller than or equal to the current minimum. If it is, we push it onto the second stack.
Step 6: When we want to find the minimum element, we can simply look at the top of the second stack, which gives us the minimum in constant time, O(1).
Step 7: Therefore, using a secondary stack allows us to find the minimum element efficiently.
