#include <bits/stdc++.h>
using namespace std;
using ll=long long;
#define rep(i,a,b) for (int i=(int)(a);i<(int)(b);i++)

vector<ll> candy(vector<ll> v, int K){
    int N = v.size();
    vector<int> L(N), R(N);
    rep(i, 0, N) L[i] = i - 1, R[i] = i + 1;
    auto del = [&](int ind) -> void {
        if (ind == -1 || ind == N) return;
        if (L[ind] == -1){
            if (R[ind] != N) L[R[ind]] = -1;
        }
        else{
            if (R[ind] == N) R[L[ind]] = N;
            else{
                int l = L[ind];
                int r = R[ind];
                R[l] = r;
                L[r] = l;
            }
        }
        R[ind] = -1;
    };
    vector<ll> ans = {0};
    priority_queue<pair<ll, int>> pq;
    rep(i, 0, N) pq.push({v[i], i});
    rep(rp, 0, (N + 1) / 2){
    	if ((int)ans.size() > K) break;
        while (true){
            auto [val, ind] = pq.top();
            pq.pop();
            if (R[ind] == -1 || v[ind] != val){
                continue;
            }
            ans.push_back(ans.back() + val);
            int l = L[ind];
            int r = R[ind];
            del(ind);
            if (l == -1 || r == N){
                del(l), del(r);
            }
            else{
                del(r);
                v[l] = v[l] - v[ind] + v[r];
                pq.push({v[l], l});
            }
            break;
        }
    }
    return ans;
}

void solve();
// POP'N ROLL MUSIC / TOMOO
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t = 1;
    cin >> t;
    rep(i, 0, t) solve();
}

void solve(){
    int N, K;
    cin >> N >> K;
    vector<ll> A(N + 1), B(N + 1);
    rep(i, 0, N) cin >> A[i + 1];
    rep(i, 0, N) cin >> B[i + 1];
    const ll inf = (1ll << 50);
    B[0] = -inf;
    vector<pair<int, ll>> p;
    N++;
    if (K % 2 == 0){
        A.push_back(0);
        B.push_back(-inf);
        N++;
        K++;
    }

    B.push_back(0);
    A.push_back(-inf);
    N++;

    ll ans = 0;

    // 圧縮する
    rep(i, 0, N){
        if (A[i] >= B[i]) p.push_back({0, A[i] - B[i]});
        else p.push_back({1, B[i] - A[i]});
        ans += max(A[i], B[i]);
    }
    vector<ll> C;
    for (int l = 0, r = 0; l < N; l = r){
        while (r != N && p[l].first == p[r].first) r++;
        ll tmp = 0;
        rep(i, l, r) tmp += p[i].second;
        C.push_back(-tmp);
    }

    // S[i] != T[i] の index の数を　K に置き換える
    K = max(0, (int)(C.size()) - 1 - K);
    K /= 2;
    // C に対して、JOI 飴を解き、ans に加算する
    ans += candy(C, K)[K];

    // 答えの出力
    cout << ans << "\n";
}