Q3. Vector STL#3

#1

Predict the time complexity of the following recursive function, given the vector is of size N and the initial call is calSum(v, 0).

int sum = 0;
void calcSum(vector v, int i)
{
if(i == v.size())
return;
sum += v[i];
calcSum(v, i+1);
}

how it is O(n^2) ?

#2

since the vector is being passed by value, it will be copied to a new vector in each call. Copying the vector will take O(n) time, doing so n times will make the overall time complexity of the program as O(n*n)