方法一

#include<iostream>

using namespace std;

int lcm(int a, int b)
{
    for(int i = 1;i <= a * b;i ++)
        if(i % a == 0 && i % b == 0)
            return i;
}

int main()
{
    int a, b;
    cin >> a >> b;

    //if(a > b) swap(a, b);

    cout << lcm(a, b) << endl;

    return 0;
}

方法二

#include<iostream>

using namespace std;

int lcm(int a, int b)
{
    for(int i = a,j = 1;;i = a * j,j ++)
    {
        if(i % b == 0) return i;
    }

}

int main()
{
    int a, b;
    cin >> a >> b;

    if(a > b) swap(a, b);

    cout << lcm(a, b) << endl;

    return 0;
}