求助 15pts

#include<bits/stdc++.h>
using namespace std;
#define ll long long
int n,a[200020],b[200020],i,ans=-2147483647,k;


int main(){
	ll c,T;
	cin>>c>>T;
	while(T--)
	{
		ans=-1;
		cin>>n>>k;
		memset(a,0,sizeof(a));
	  	for(int i=1;i<=n;i++) 
	  	{
	  		cin>>a[i];	
		}
		sort(a+1,a+n+1);
		b[1]=k;
		for(int i=2;i<=n;i++) 
	  	{
		  	
	  		b[i]=k-a[i]+a[i-1];
	  		//<<a[i]<<" ";
		}
		int ans=b[1],mo=b[1];
	   for(i=2;i<=n;i++){
	       //if(i==1) b[i]=a[i];
	       mo=max(b[i],mo+b[i]);
	       ans=max(ans,mo);
	   }
	   cout<<ans<<endl;
	}
   	
   return 0;
}