https://codeforces.com/contest/1945/problem/D

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> PII;
typedef vector<long long> VI;
#define rep(i,a,n) for (int i=a;i<=n;i++)
#define per(i,a,n) for (int i=a;i>=n;i--)
#define pb(i) push_back(i)
#define int long long
#define INF 0x3f3f3f3f
#define oz  998244353
#define endl '\n'
#define N 200010
const int mod = 1e9 + 7;


int p[N], si[N];
int find(int x) {
    if (x != p[x]) p[x] = find(p[x]);
    return p[x];
}
//size[find(b)] += size[find(a)];
//p[find(a)] = find(b);



void solve() {
    int n, m;
    cin >> n >> m;

    VI a(n), b(n);
    rep(i, 0, n - 1)cin >> a[i];
    rep(i, 0, n - 1)cin >> b[i];

    int sum = 0;
    int res = 1e18;

    per(i, n - 1, 0) {
        if (i < m) {
            res = min(res, sum + a[i]); //在前m个人中找最小方案
        }

        sum += min(a[i], b[i]); //每次贪心选取较小价值
    }

    cout << res << endl;

}

signed main() {

    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);

    int T = 1;
    cin >> T;
    while (T --)

        solve();

    return 0;
}