题解 | 数组取精

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
    int n;
    cin>>n;
    vector<pair<long long,int>> arr_a;
    vector<pair<long long,int>> arr_b;
    for(int i=0;i<n;i++){
        long long k;
        cin>>k;
        arr_a.emplace_back(k, i+1);
    }
    for(int i=0;i<n;i++){
        long long k;
        cin>>k;
        arr_b.emplace_back(k, i+1);
    }
    sort(arr_a.begin(),arr_a.end(),[](const pair<long long,int>& a,const pair<long long,int>& b){
        return a.first>b.first;
    });
    vector<int> S;
    S.push_back(arr_a[0].second);
    for(int i=1;i<n&&i+1<n;i+=2){
        int index=arr_b[arr_a[i].second-1].first>=arr_b[arr_a[i+1].second-1].first? arr_a[i].second:arr_a[i+1].second;
        S.push_back(index);
    }
    if(n%2==0) S.push_back(arr_a[n-1].second);
    cout<<S.size()<<endl;
    int tmp=S.size();
    for(int i=0;i<tmp;i++){
        cout<<S[i]<<(i==tmp-1?"":" ");
    }
    return 0;
}  
// 64 位输出请用 printf("%lld")