One way to create a task is to learn from math. You can generate some random math statement or modify some theorems to get something new and build a new task from that.
For example, there is a statement called the “Goldbach’s conjecture”. It says: “each even number no less than four can be expressed as the sum of two primes”. Let’s modify it. How about a statement like that: “each integer no less than 12 can be expressed as the sum of two composite numbers.” Not like the Goldbach’s conjecture, I can prove this theorem.
You are given an integer n no less than 12, express it as a sum of two composite numbers.
Input
The only line contains an integer n (12 ≤ n ≤ 10）
Output
Output two composite integers x and y (1 < x, y < n) such that x + y = n. If there are multiple solutions, you can output any of them.
#include <iostream>
using namespace std;
int main()
{
int n;
cin >> n; int x=0;
for (int i = n / 2; i > 1; i--)
{
int k = n - i;
for (int j = 2;j<k; j++)
{
if (k%j==0)
{
for (int y = 2;y<i; y++)
if (i%y==0)
{
x = 1; break;
}
}
}
if (x)
{
cout << k << " " << i; break;
}
}
}