#include <iostream>
using namespace std;
//Write a method to randomly generate a set of m integers from an array of size n. Each
// element must have equal probability of being chosen.
void printArray(int a[], int n)
{
for(int i=0; i<n; i++)
{
cout << a[i] << " ";
}
cout << endl;
}
void shuffle(int a[], int n)
{
for(int i=n-1; i>=1; i--)
{
swap(a[i], a[rand()%(i)]);
}
}
void randomSet(int a[], int n, int b[], int m)
{
if(m>n)
return;
for(int i=n-1, j=0; i>=1 && j<m; i--, j++)
{
int k = rand()%(i);
b[j] = a[k];
swap(a[i], a[k]);
}
}
int main() {
// your code goes here
int a[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
int b[100];
printArray(a, sizeof(a)/sizeof(a[0]));
// shuffle(a, sizeof(a)/sizeof(a[0]));
printArray(a, sizeof(a)/sizeof(a[0]));
randomSet(a, sizeof(a)/sizeof(a[0]), b, sizeof(a)/sizeof(a[0]) - 4);
printArray(b, sizeof(a)/sizeof(a[0]) - 4);
return 0;
}
