Delete nodes from bst

#1

#include
#include
using namespace std;
class node {
public:
int data;
node* left;
node* right;

node (int d)
{
    data = d;
    left = NULL;
    right = NULL;
}

};

node* build (node* root, int *arr, int s, int e)
{
if (s>e) return NULL;
int mid = (s+e)/2;
root = new node (arr[mid]);
root->left = build (root->left, arr, s, mid-1);
root->right = build (root->right, arr, mid+1, e);
return root;
}

node* deleteBST (node* root, int key)
{
if (root==NULL) return NULL;
else if (key < root->data) {
root->left = deleteBST (root->left, key);
return root; }
else if (key > root->data) {
root->right = deleteBST (root->right, key);
return root; }
else {
if (root->left==NULL && root->right==NULL) {
delete root;
return NULL;
} else if (root->left==NULL && root->right!=NULL) {
node* temp = root->right;
delete root;
return temp;
} else if (root->right==NULL && root->left!=NULL) {
node* temp = root->left;
delete root;
return temp;
} else {
node * replace = root->left;
while (replace ->right!=NULL)
{
replace = replace->right;
}
root->data = replace ->data;
root->left = deleteBST (root->left, replace->data);
return root;
}
}
}

void printPre (node* root)
{
if (root==NULL) return;
cout << root->data <<" ";
printPre (root->left);
printPre (root->right);
}

int main ()
{
int test;
cin >> test;
while (test>0){
int n;
cin >> n;
int arr [n];
for (int i=0; i<n; i++)
{
cin >> arr[i];
}
sort (arr, arr+n);
node* root = NULL;
root = build (root, arr, 0, n-1);
int m ;
cin >> m;
for (int i=0; i<m; i++)
{
int d;
cin >> d;
root = deleteBST(root, d);
}
printPre (root);
test–;
}
}
why it is showing segmentation fault?