poj 2547 No Tipping

#include<iostream>#include<cstdio>#include<cstring>using namespace std;double l,w,n;bool visited[1<<22];struct P{    double x;    double wt;    double lt,rt;}pack[30];int res[30];bool solve(int dep,double l,double r,int state){    int i;    if(dep==n)  return true;    if(visited[state])  return false;    visited[state]=true;    if(l<0||r>0)  return false;    for(i=0;i<n;i++)    {        int tmp=1<<i;        if((tmp&state)!=0)  continue;        res[dep]=i;        if(solve(dep+1,l-pack[i].lt,r-pack[i].rt,(state|tmp))) return true;    }    return false;}int main(){    double left,right;    int t=1;    int i;    while(scanf("%lf%lf%lf",&l,&w,&n)==3)    {        if(l+w+n==0)  break;        left=1.5*w;        right=-left;        for(i=0;i<n;i++)        { scanf("%lf%lf",&pack[i].x,&pack[i].wt); pack[i].lt=(pack[i].x+1.5)*pack[i].wt; pack[i].rt=(pack[i].x-1.5)*pack[i].wt; left+=pack[i].lt; right+=pack[i].rt;        }        memset(visited,false,sizeof(visited));        printf("Case %d:n",t++);        if(solve(0,left,right,0))        { for(i=0;i<n;i++)     printf("%.0lf %.0lfn",pack[res[i]].x,pack[res[i]].wt);        }        else printf("Impossiblen");    }    return 0;}