Question 3-3. (10 points) Describe the process of divide-and-conquer and then complete the following quick sort algorithm.

void QS(float a[], int p, int r)

{

if (p

int q = partition(a, p, r);

(1) ;

(2) ;

}

Question 3-4. (10 points) Describe the idea of back-tracking and write a program to solve the 4-Queen problem.