uva 11078

shui题

 #include <iostream>
 #include <cstring>
 #include <algorithm> 
 #include <cmath>
 using namespace std;
const int N=1e5+5;
  int a[N];
  int n,m;
  
  void solve(){
  	int i,t,ans=-1e9;
  	cin>>n;
  	for(i=1;i<=n;i++) cin>>a[i];
	t=a[1];
  	
  	for(i=2;i<=n;i++){
  		ans=max(ans,t-a[i]);
  		t=max(t,a[i]);
	  }
	  cout<<ans<<endl;
  }
 int main(){
 	int cas;
 	cin>>cas;
 	while(cas--) solve();
 }