Question

Write some code (not from the course or web) that runs in f(n) = 2n² + 4n time, where n is the size of the input.

You may write it as a Java method or a C++ function.

The method/function will have one parameter, an integer named numItems, which represents the size of the input.

Answer 1

void function(int numItems) {
    int count = 0;
    for(int i = 0; i < 2*numItems; ++i) {
        for(int j = 0; j < numItems; ++j) {
            count++;
        }
    }
    for(int i = 0; i < 4*numItems; ++i) {
        count++;
    }
}

$\color{red}This\;runs\;in\;2n^2+4n$