R Data Structures and Algorithms

Exercises

1. What will be the top value for the following stack operations?

         PUSH(1) 
         PUSH(2) 
         PUSH(6) 
         PUSH(3) 
         POP() 
         POP()
   

2. Assume a stack with the elements {1, 2, 3, 5, 6, 7} in order, with 7 on top. Write the operations required to insert 4 after 3 in the current stack.
3. Explain the difference in the outputs of the following recursion functions:

   Output 1	Output 2
   problemfun1<-function(n){ if(n<1) return(1) problemfun1(n-1) print(n) }	problemfun1<-function(n){ if(n<1) return(1) print(n) problemfun1(n-1) }

4. Write a recursive algorithm to evaluate the Fibonacci sequence. (In a Fibonacci sequence, each item is the sum of the previous two.)
5. Write a function to invert the values in a stack.
6. Write a function to implement two stacks using only one ...