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

#1

int sum = 0;
void calcSum(vector v, int i)
{
if(i == v.size())
return;
sum += v[i];
calcSum(v, i+1);
}
why it’s time complexity is O(N^2) ???

#2

See this, it’s call by value method. Every time vector v gets copied in some other vector thus a vector of size n gets copied in another vector that too n times gives a resultant of o(N^2).

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#3

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