$\text{Link}$

#include <iostream>
#include <cmath>
#include <algorithm>
using namespace std;
long long a[200011], b[200011];
long long m, n, top, sum;
int main() {
	cin >> m >> n;
	for (long long i = 0; i <= m - 1; i++) {
		cin >> a[i];
	}
	for (long long i = 0; i <= n - 1; i++) {
		cin >> b[i];
	}
	sort(a, a + m);
	sort(b, b + n);
	for (long long i = 0; i <= n - 1; i++) {
		long long dx = abs(a[i] - b[top]);
		while (abs(a[i] - b[top + 1]) <= dx) {
			top++;
			dx = abs(a[i] - b[top]);
		}
		sum += dx;
	}
	cout << sum;

}

样例过了，但不对喵。