what's wrong with code?
I get wrong answer every time.

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n,min=99;
    cin>>n;
    int arr[n];
    for(int i=0;i<n;i++)
    {
        cin>>arr[i];
    }
    for(int j=1;j<n;j++)
    {
        int max=arr[j]-arr[j-1];

        if(max<min && max>=0)
        {
            min=max;
        }

    }

    cout<<min<<endl;

}

1) Why do you initialize min as 99? Weights can be up to 10^5.
2) This problem can't be solved so easily. It requires to examine all options (2^n in total). You can use recursive function, for example.