#include <iostream>
#include <algorithm>
using namespace std;

int x1, y1, x2, y2;
int sum;

int main()
{
    int arr[9] = {1,2,3,4,5,6,7,8,9};
    while(next_permutation(arr, arr+9))
    {
        sum = 1000*arr[0] + 100*arr[1] + 10*arr[2] + arr[3];
        x1 = arr[4];
        y1 = 1000*arr[5] + 100*arr[6] + 10*arr[7] + arr[8];//第一种组合情况
        
        x2 = 10*arr[4] + arr[5];
        y2 = 100*arr[6] + 10*arr[7] + arr[8];//第二种组合情况

        if(sum == x1*y1)
        {
            cout << sum << " = "<< x1 << " x " << y1 << endl;
        }
        else if(sum == x2*y2)
        {
            cout << sum << " = "<< x2 << " x " << y2 << endl;
        }

    }

   
    return 0;
}

#include<iostream>
using namespace std;
int main()
{
    cout<<"4396 = 28 x 157"<<"\n"
		<<"5346 = 18 x 297"<<"\n"
		<<"5346 = 27 x 198"<<"\n"
		<<"5796 = 12 x 483"<<"\n"
		<<"5796 = 42 x 138"<<"\n"
		<<"6952 = 4 x 1738"<<"\n"
		<<"7254 = 39 x 186"<<"\n"
		<<"7632 = 48 x 159"<<"\n"
		<<"7852 = 4 x 1963"<<endl;
    return 0;
}

参考答案：

#include<iostream>
using namespace std;
int main()
{
    cout << "4396 = 28 x 157" << endl;
    cout << "5346 = 18 x 297" << endl;
    cout << "5346 = 27 x 198" << endl;
    cout << "5796 = 12 x 483" << endl;
    cout << "5796 = 42 x 138" << endl;
    cout << "6952 = 4 x 1738" << endl;
    cout << "7254 = 39 x 186" << endl;
    cout << "7632 = 48 x 159" << endl;
    cout << "7852 = 4 x 1963" << endl;

    return 0;
}