CodeForces 203C Photographer

简单贪心。注意内存够大，能满足所有顾客的特殊情况。

 #include <iostream>
 #include <cstring>
 #include <algorithm>

 #define maxn 100010

 using namespace std;

 typedef long long ll;

 struct node {
 ll c,id;
 }c[maxn];

 bool cmp (node x,node y){
 if (x.c<y.c)
 return true ;
 return false ;
 }

 int main (){
 ll n,d,x,y,a,b;
 ll ans,sum;
 while (cin>>n>>d){
 cin>>a>>b;
 for (int i=;i<n;i++){
 cin>>x>>y;
 c[i].c=a*x+b*y;
 c[i].id=i+;
 }
 sort (c,c+n,cmp);
 sum=ans=;
 for (int i=;i<n;i++){
 sum+=c[i].c;
 if (sum>d){
 ans=i;
 break ;
 }
 if (i==n-) //所有顾客都能满足
 ans=n;
 }
 cout<<ans<<endl;
 for (int i=;i<ans;i++){
 cout<<c[i].id<<" ";
 }
 cout<<endl;
 }
 return ;
 }