1478测试点3、5不过，哪个好朋友帮帮忙

#include<cstdio>
#include<algorithm>
#include<map>
#include<iostream>
#include<vector>

using namespace std;
typedef pair<int, int> PAIR;

bool cmp(PAIR a, PAIR b) {
    return a.second < b.second;
}
int main()
{
    int n , s , a , b , number = 0 ;
    map<int,int> comp;
    map<int, int>::iterator iter;
    vector<PAIR> vcomp;
    vector<PAIR>::iterator viter;
    cin >> n >> s >> a >> b ;
    int height = a + b ;
    int xi , yi ;
    while(n > 0){
        cin >> xi >> yi ;
        comp.insert(make_pair(xi,yi));
        n -- ;
    }
    for(iter=comp.begin(); iter!=comp.end(); iter++) {
        vcomp.push_back(PAIR(iter->first, iter->second));
    }
    sort(vcomp.begin(), vcomp.end(), cmp);
    for(viter=vcomp.begin(); viter!=vcomp.end(); viter++) {
        if ( viter -> second <= s  && viter -> first <= height ){
            s -= viter -> second ;
            number ++ ;
        }
    }
    cout << number << endl;
    return 0;
}