Hello my dear friends @codeforces!

my team failed to solve **Problem H of Tehran ICPC 2018** during the contest. I tried to solve it with a **greedy** algorithm after the contest but I failed. I have the test cases, and even when I solve the failed test case with hand, it ends with a wrong answer always **greater** than the accepted answer. this shows my approach is totally wrong. I thought a lot about the problem, but no other algorithm comes to my mind. can anyone help me to solve it?

this is the code that fails.

```
//TEHRAN SITE
//2018-Problem H
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main(void)
{
int n, smaller, bigger;
cin >> n >> smaller >> bigger;
if(bigger < smaller)
swap(smaller, bigger);
vector <int> coordinates(n);
for(int i = 0; i < n; ++i)
cin >> coordinates[i];
sort(coordinates.begin(), coordinates.end());
vector <int> anntena(n, smaller);
for(int i = 0; i < n; ++i){
int max_dis = max((i - 1 >= 0 ? coordinates[i] - coordinates[i - 1] : 0)
, i + 1 < n ? coordinates[i + 1] - coordinates[i]: 0);
if(max_dis > smaller)
anntena[i] = bigger;
if(max_dis > bigger){
cout << -1 << endl;
return 0;
}
}
long long int result = 0;
for(auto a : anntena)
result += a;
cout << result << endl;
return 0;
}
```