#include <bits/stdc++.h>
#define ll long long
 
using namespace std;
 
const int MOD = 1e9 + 7;
 
void solve(){
	ll n, k;
	cin >> n >> k;
 
	vector<pair<int, int>> a(n);
 
	for(int i = 0; i < n; i++){
		cin >> a[i].first;
	}
 
	for(int i = 0; i < n; i++){
		cin >> a[i].second;
	}
 
	sort(a.begin(), a.end());
	ll ans = 0;
	int idx = -1;
	for(int i = n - 1; i >= 0; i--){
		if(a[i].second == 1){
			if(i > (n - 1) / 2 - (n % 2)){
				ans = max(ans, a[i].first + a[(n - 1) / 2 - (n % 2)].first + k);
			}else{
 
				ans = max(ans, a[i].first + k + a[(n - 1) / 2 + !(n % 2)].first);
			}
		}else{
			idx = max(idx, i);
		}
 
	}
	if(idx == -1){
		cout << ans << "\n";
		return;
 
	}
 
 
 
	ll s = 0, e = 1e10;
 
	while(s <= e){
		ll rem = k;
		ll mid = s + (e - s) / 2;
		vector<pair<int, int>> b;
 
		for(int i = 0; i< n; i++){
			if(i == idx)continue;
			b.push_back(a[i]);
		}
 
		for(int i = n - 2; i >= 0; i--){
			if(b[i].second == 1 && b[i].first < mid){
				ll p = min(rem, mid - b[i].first);
				b[i].first += p;
				rem -= p;
			}
		}
		sort(b.begin(), b.end());
		if(b[(n - 2) / 2].first >= mid){
			ans = max(ans, a[idx].first + mid);
			s = mid + 1;
		}else{
			e = mid - 1;
		}
	}
	cout << ans << "\n";
}
 
int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
 
	int t = 1;
	cin >> t;
 
	for(int i = 1; i <= t; i++){
		solve();
	}
	return 0;
}

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8
2 10
3 3
1 1
3 10
3 3 3
0 0 0
4 4
2 1 5 1
0 1 0 1
5 4
7 5 2 5 4
0 0 1 0 1
5 1
5 15 15 2 11
1 0 0 1 1
5 2
10 11 4 10 15
1 1 0 1 0
4 4
1 1 2 5
1 1 0 0
2 1000000000
1000000000 1000000000
1 1