The function takes a string containing only three types of characters - '(', ')' and '*' - and returns whether the string is valid according to the following rules: 1. Any left parenthesis '(' must have a corresponding right parenthesis ')'. 2. Any right parenthesis ')' must have a corresponding left parenthesis '('. 3. Left parenthesis '(' must go before the corresponding right parenthesis ')'. 4. '*' could be treated as a single right parenthesis ')' or a single left parenthesis '(' or an empty string. 5. An empty string is also valid.

221

Nov 05
Given a string of parentheses, this algorithm determines whether the string is balanced. A string is balanced if it contains as many opening parentheses as it does closing parentheses, and if each opening parenthesis is matched with a closing parenthesis that appears after it in the string.

168

Nov 05
A queue can be implemented using two stacks. In this implementation, one stack is used for enqueueing items, and the other stack is used for dequeueing items. When an item is enqueued, it is pushed onto the enqueue stack. When an item is dequeued, it is popped from the dequeue stack. If the dequeue stack is empty, then the items in the enqueue stack are popped and pushed onto the dequeue stack.

225

Nov 03
This function takes in a string of parentheses and determines if it is balanced. A string is balanced if each opening parentheses has a corresponding closing parentheses and the order of the parentheses is maintained.

211

Nov 03
To find the median of a stream of integers, we can use a min heap and a max heap. We can keep track of the median by comparing the top elements of the heaps. If they are equal, then the median is the average of those two numbers. If the max heap has more elements, then the median is the top element of the max heap. Otherwise, the median is the top element of the min heap.

205

Nov 03
Write a function that takes in a list of integers and returns the sum of the integers at odd indices.

197

Oct 24
This problem asks you to write a function that returns the largest integer in a given list. For example, if the input list is [1, 2, 3, 4, 5], the largest integer in the list is 5.

217

Oct 23