题目1336：液晶屏裁剪-----------注意辗转相除法，还要几点注意的地方

#include<stdio.h>
int com_div(int a,int b)//辗转相除法
{
        int r;
        while(b!=0)
        {
                r=a%b;
                a=b;
                b=r;
        }
        return a;
}
int main()
{
        int a,b,x,y,a1,b1,t,i;
        while(scanf("%d%d%d%d",&a,&b,&x,&y)!=EOF)
        {
                t=com_div(x,y);
                x=x/t;
                y=y/t;
                if(a<x||b<y)
                {
                        printf("0 0\n");
                        continue;
                }
                if(x>y)
                {
                        for(a1=a/x*x;a1/x*y>b;a1-=x);
                        b1=a1/x*y;
                }
                else
                {
                        for(b1=b/y*y;b1/y*x>a;b1-=y);
                        a1=b1/y*x;
                }
                printf("%d %d\n",a1,b1);
        }
        return 0;
}