#include <bits/stdc++.h>
using namespace std;
struct app{
    int x,y;
};
bool cmp(app a,app b){
    return (a.y<=b.y);
}
int s,n,b,a,num;
int main(){
    cin>>n>>s;
    cin>>a>>b;
    app apple[5000];
    for(int i=0;i<n;i++){
        cin>>apple[i].x>>apple[i].y;
    }
    sort(apple,apple+n,cmp);
    for(int i=0;i<n;i++){
        if(s>apple[i].y){
            if(apple[i].x<=(a+b)){
                num++;
                s-=apple[i].y;
            }
        }
    }
    cout<<num<<endl;
    return 0;
}

这道题用dev测试完全可行,在洛谷上确是: #1WA #2AC #3RE #4AC #5AC 到底是哪里出了问题?悬关求助!