HDU 1155 Bungee Jumping

#include<stdio.h>
#include<stdlib.h>
int main()
{
    double k,l,s,w;
    while( scanf( "%lf%lf%lf%lf",&k,&l,&s,&w ),k||l||s||w )
    {
        if( l>=s )//当绳子大于桥的高度就只要判断势能转化成动能
        {
            if(s>(100/19.62)) printf( "Killed by the impact.\n" );
            else printf( "James Bond survives.\n" );
        } 
        else 
            {
               double p0=k*(s-l)*(s-l);
               double Ep=2*w*9.81*s;
               double E=Ep-p0,Ek=w*10*10;
               if( p0>Ep )//当重力势能小于弹性势能就停在空中
                printf( "Stuck in the air.\n" );
                else if( E>Ek )//当重力势能大于弹性势能与速度10的动能
                      printf( "Killed by the impact.\n" );
                      else printf( "James Bond survives.\n" );
            }      
    }
   return 0;    
}