पोस्टफिक्स अभिव्यक्ति (postfix expression): 1 2 3 * + 5 - का मूल्यांकन करने पर क्या परिणाम प्राप्त होगा?

What is the worst-case time complexity of inserting 'n' elements into an initially empty linked list such that the linked list remains sorted?

What are the contents of an initially empty stack (from bottom to top) after performing the following operations? PUSH(A); PUSH(B); PUSH(C); POP; PUSH(D); POP; POP; PUSH(E); PUSH(F); POP;