Hello, this is my first problem on segment tree. I have used segment tree to solve this problem but I am getting Wrong Answer on a test case. Can you point out what is wrong. Thank you

Problem Statement ~~~~~

include

include

include

include

using namespace std; struct list { long sum,bestsum,left,right; };

list* make_new_node(long s,long bs,long l,long r) { list* temp=new list(); temp->sum=s; temp->bestsum=bs; temp->left=l; temp->right=r; return temp; }

void build(long arr[],list* tree[],int node,int low,int high) { if(low>high) return; if(low==high) { tree[node]=make_new_node(arr[low],arr[low],arr[low],arr[low]); return; }

build(arr,tree,2*node+1,low,(high+low)/2);
build(arr,tree,2*node+2,(high+low)/2+1,high);

// tree[node]=NULL; long a=tree[2*node+1]->sum+tree[2*node+2]->sum; long b=max(max(tree[2*node+1]->bestsum,tree[2*node+2]->bestsum),tree[2*node+1]->right+tree[2*node+2]->left); long c=max(tree[2*node+1]->left,tree[2*node+1]->sum+tree[2*node+2]->left); long d=max(tree[2*node+1]->right+tree[2*node+2]->sum,tree[2*node+2]->right);

tree[node]=make_new_node(a,b,c,d);

}

list* query(list* tree[],int node,int low,int high,int l,int r) { if(low>high || low>r || high<l) return make_new_node(-15008,-15008,-15008,-15008); if(low>=l && high<=r) return tree[node];

list *a=query(tree,2*node+1,low,(high+low)/2,l,r);
list *b=query(tree,2*node+2,(high+low)/2+1,high,l,r);

long w=a->sum+b->sum;
long x=max(max(a->bestsum,b->bestsum),a->right+b->left);
long y=max(a->left,a->sum+b->left);
long z=max(a->right+b->sum,b->right);
tree[node]=make_new_node(w,x,y,z);

return tree[node];

}

int main() { //ios_base::sync_with_stdio(false); int n; scanf("%d",&n); // cin>>n; long arr[n]; list* tree[5*n]; for(int i=0;i<n;i++) scanf("%ld",&arr[i]); // cin>>arr[i]; build(arr,tree,0,0,n-1);

int q;
scanf("%d",&q);
for(int i=0;i<q;i++)
{
    int l,r;
    scanf("%d%d",&l,&r);

// cout<<query(tree,0,0,n-1,l-1,r-1)->bestsum<<endl; printf("%ld\n",query(tree,0,0,n-1,l-1,r-1)->bestsum); } return 0; }

~~~~~