#include<iostream>
#include<algorithm> 
using namespace std;
int n,s,a,b,x_,y_,can,rest,ans;
struct apple{
    int xi,yi;
}ap[50005];
int cmp(apple x,apple y){
    return x.yi<y.yi;
}
int main(){
    cin>>n>>s>>a>>b;
    for(int i=1;i<=n;i++){
        cin>>x_>>y_;
        if(x_<=a+b){
            can++;
            ap[can].xi=x_;
            ap[can].yi=y_;
        }
    }
    sort(ap+1,ap+can+1,cmp);
    rest=s;
    ans=0;
    for(int i=1;rest>=ap[i].yi&&i<=can;i++){
        ans++;
        rest-=ap[i].yi;
    }
    cout<<ans;
    return 0;
} 

需要排序，利用结构体即可。

#include<bits/stdc++.h> using namespace std; int n, s, a, b, x[5010], y[5010], p[5010], i, j, sum; int main() { cin >> n >> s >> a >> b; b += a; for (i = 0; i < n; i ++) { cin >> x[i] >> y[i]; if (x[i] > b)p[i] = 1; } for (i = 0; i < n; i ++) for (j = i + 1; j < n; j ++) if (y[i] > y[j]) { swap(y[i], y[j]); swap(x[i], x[j]); swap(p[i], p[j]); } for (i = 0; i < n; i ++) { if (p[i])continue; if (s >= y[i])s -= y[i], sum ++; } cout << sum << "\n"; return 0; }