#include <bits/stdc++.h>
using namespace std;
int main() {
int n; cin >> n;
vector<int> arr(n);
for(int i = 0; i < n; i++)
cin >> arr[i];
unordered_map<int,vector<pair<int,int>>> mp;
vector<vector<int>> res;
for(int k = 2; k < n-1; k++){
int j = k-1;
for(int i = 0; i < j; i++){
int sum = arr[i]+arr[j];
mp[sum].push_back({i,j});
}
for(int l = k+1; l < n; l++){
int target = -1*(arr[k]+arr[l]);
if(mp.find(target)!=mp.end()){
vector<pair<int,int>> temp = mp[target];
for(int x = 0; x < temp.size(); x++){
cout << temp[x].first << " " << temp[x].second << " " << k << " " << l << endl;
}
}
}}
return 0;
}
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