View Code of Problem 104

#include<stdio.h>
#include<math.h>
int main()
{
	int n,v1,v2,t;
	double time;
	while( scanf("%d%d%d%d",&n,&v1,&v2,&t)!=EOF )
	{
		if( (v1>0&&v2>0&&v1<=v2) || (v1<0&&v2<0&&fabs(v2)<=fabs(v1)) )
		{
			printf("NO\n");
		}
		else if(v1<=0&&v2>=0)
		{
			printf("NO\n");
		}
		else if(v1>=0&&v2<=0)
		{
			time = n*1000.0/(v1+fabs(v2));
			if(time<=t)
			{
				printf("%.2f\n",time);
			}
			else
			    printf("NO\n");
		}
		else if(v1>0&&v2>0)
		{
			time = n*1000.0/(v1-v2);
			if(time<=t)
			printf("%.2f\n",time);
			else
			printf("NO\n");
		}
		else if(v1<0&&v2<0)
		{
			time = n*1000.0/(fabs(v2)-fabs(v1));
			if(time<=t)
			  printf("%.2f\n",time);
			else
			  printf("NO\n");
		}
	} 
	return 0;
 }