Question

You are given a list, L, and another list, P, containing integers sorted in ascending order. The operation printLots(L, P) will print the elements in L that are in positions specified by P. For instance, if P = 1, 3, 4, 6, the elements in positions 1, 3, 4, and 6 in L are printed. Write the procedure printLots(L, P). You may use only the public STL container operations. What is the running time of your procedure?

Answer 1

The solution is provided in the code snippet provided below using vector of STL.

Vector are same as dynamic arrays placed in contiguous storage .

// printLots prints elements in vector L at positions specified in vector P
void printLots(vector<int> L, vector<int> P)          
{
    // This for loop runs for every element in P
    // P.size() returns the number of elements in vector P
    for (int i = 0; i < P.size(); i++) 
    {
        // This line will print elememts in L where i is the current position accessed in P  
        // and (P[i] - 1) is the required position in L 
        // since the vector starts from 0th location.
        cout << L[ P[i] - 1 ]<<" ";      
    }
}

The running time of this procedure is equal to the number of elements/values in vector P which will be equal to P.size() as for loop runs P.size() times.