a) Calculate the number of times the following loop executes. for i 1 to n for j-i1 ton /do something without branching next j next i Write pseudocode for an algorithm which uses a stack to match parenthesis. That is, the 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 ( ) 1 1 H ( ) }" has properly matched paienthesis. Another algorithm executes State the complexity of the algorithm using big theta notation. c) 4n-5 calculations for an input of size n. Is this algorithm O(n)