below give code is for easy problem PLYFIT and i think my approach and understanding is right but i am getting the wrong answer.
could you plz point me out the problem or maybe corner test case.
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned long long
#define MAXI INT_MAX
#define MINI INT_MIN
#define din(t) long long t;cin>>t;
#define fi(i,l,r,d) for(i = l; i < r; i+=d)
#define fd(i,l,r,d) for(i = l-1; i >= r; i-=d)
int main(){
ll t;
scanf("%lld",&t);
while(t–){
ll n;
scanf("%lld",&n);
ll arr[n]={0};
ll i,mini,ans=0;
fi(i,0,n,1)scanf("%lld",&arr[i]);
ll maxdiff=(arr[1]-arr[0]);
mini=arr[0];
fi(i,1,n,1){
if(arr[i]-mini>maxdiff)maxdiff=arr[i]-mini;
if(arr[i]<mini)mini=arr[i];
}
if(maxdiff>0)printf("%lld\n",maxdiff);
else printf(“UNFIT\n”);
}
}