#include <bits/stdc++.h>
using namespace std;

const int N = 3e5 + 5;
const int K = 70;
const long long inf = 1e18;

int T, n, k, topl, topr, x[N], v[N], id[N], rk[N], stkl[N], stkr[N];
long long ans, dp[K], ndpl[K], ndpr[K];

bool cmp(int i, int j) {
	return x[i] < x[j];
}

void work() {
	cin >> n >> k;
	k = min(k, 64);
	for (int i = 1; i <= n; i++) {
		cin >> x[i];
	}
	for (int i = 1; i <= n; i++) {
		cin >> v[i];
	}
	for (int i = 1; i <= n; i++) {
		id[i] = i;
	}
	sort(id + 1, id + n + 1, cmp);
	for (int i = 1; i <= n; i++) {
		rk[id[i]] = i;
	}
	topl = 0;
	stkl[++topl] = 1;
	for (int i = rk[1] - 1; i >= 1; i--) {
		if (v[id[i]] < v[stkl[topl]]) {
			stkl[++topl] = id[i];
		}
	}
	topr = 0;
	stkr[++topr] = 1;
	for (int i = rk[1] + 1; i <= n; i++) {
		if (v[id[i]] < v[stkr[topr]]) {
			stkr[++topr] = id[i];
		}
	}
	ans = 0x3f3f3f3f3f3f3f3f;
	memset(ndpl, 0x3f, sizeof(ndpl));
	memset(ndpr, 0x3f, sizeof(ndpr));
	ndpl[0] = 0;
	ndpr[0] = 0;
	for (int l = 1, r = 1; l <= topl || r <= topr; ) {
		if (r > topr || l <= topl && v[stkl[l]] >= v[stkr[r]]) {
			for (int j = 0; j <= k; j++) {
				dp[j] = ndpl[j];
				ans = min(ans, dp[j] + 1ll * abs(x[n] - x[stkl[l]]) * v[stkl[l]]);
			}
			memset(ndpl, 0x3f, sizeof(ndpl));
			for (int j = 0; j <= k; j++) {
				if (l + 1 <= topl) {
					ndpl[j] = min(ndpl[j], dp[j] + 1ll * (x[stkl[l]] - x[stkl[l + 1]]) * v[stkl[l]]);
				}
				if (r <= topr) {
					ndpr[j + 1] = min(ndpr[j + 1], dp[j] + 1ll * (x[stkr[r]] - x[stkl[l]]) * v[stkl[l]]);
				}
			}
			l++;
		} else {
			for (int j = 0; j <= k; j++) {
				dp[j] = ndpr[j];
				ans = min(ans, dp[j] + 1ll * abs(x[n] - x[stkr[r]]) * v[stkr[r]]);
			}
			memset(ndpr, 0x3f, sizeof(ndpr));
			for (int j = 0; j <= k; j++) {
				if (r + 1 <= topr) {
					ndpr[j] = min(ndpr[j], dp[j] + 1ll * (x[stkr[r + 1]] - x[stkr[r]]) * v[stkr[r]]);
				}
				if (l <= topl) {
					ndpl[j + 1] = min(ndpl[j + 1], dp[j] + 1ll * (x[stkr[r]] - x[stkl[l]]) * v[stkr[r]]);
				}
			}
			r++;
		}
	}
	cout << ans << '\n';
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> T;
	while (T--) {
		work();
	}

	return 0;
}