a) Write pseudocode for an algorithm which uses a stack to match parenthesis. procedure accepts a string of characters consisting of left and right brackets and determines whether or not the brackets are properly matched. For example, the string ! ( ) { I l }l ( ) }" has prperly matched parenthesis. That is, the b) Another algorithm executes 4n-5 calculations for an input of size n. Is this algorithm O(n)? State the complexity of the algorithm using big theta notation