C. Minimum Extraction(1000)

#include<bits/stdc++.h>
using namespace std;
bool cmp(int x,int y){
    return x > y;
}
int a[200005],b[200005];
int main(){
    int t,n;
    scanf("%d",&t);
    while(t--){
    int maxn=-1000000005;
        scanf("%d",&n);
        for(int i=1;i<=n;i++){
            scanf("%d",&a[i]);
        }
        sort(a+1,a+1+n,cmp);
        int sum=a[n];
        b[n]=a[n];
        for(int i=n;i>0;i--){
            b[i-1]=a[i-1]-sum;
            sum+=b[i-1];
        }
        for(int i=1;i<=n;i++){
            if(b[i]>maxn){
                maxn=b[i];
            }
        }
        printf("%d\n",maxn);    
    }
}