View Code of Problem 104

#include<stdio.h>
#include<math.h>

int main(){
	int n,v1,v2,t,flag;
	double a;
	while(scanf("%d%d%d%d",&n,&v1,&v2,&t)!=EOF)
	{
		
		flag=0;
		if(v1<=0 && v2>=0 )
			flag=0;
		else if(v1<=0 && v2<=0 )
		{   a=1.0*n*1000/fabs((v1-v2));
		    if(a<=t*1.0)
				flag=1;
			else
				flag=0;
		}
		else 
		{   a=1.0*n*1000/fabs((v1-v2));
		    if(a<=t*1.0)
				flag=1;
			else
				flag=0;
		}

		if(flag==1)
			printf("%0.2f\n",a);		
		else
			printf("NO\n");
				
	}
	return 0;
}