ABC D求条 玄3关

#include<bits/stdc++.h>
#define int long long
const int mod = 998244353;
using namespace std;
int a[500005], b[500005], x[500005];
signed main() {
	int n, m;
	cin >> n >> m;
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
	}
	for (int i = 1; i <= m; i++) {
		cin >> b[i];
	}
	sort(a + 1, a + 1 + n);
	sort(b + 1, b + 1 + m);
	int sum = 0, i = 1, j = 1;
	while (i <= n && j <= m) {
		if (a[i] < b[j]) {
			sum = (sum + (b[j] - a[i]) * (m - j)) % mod;
			i++;
		} else {
			sum = (sum + (a[i] - b[j]) * (n - i)) % mod;
			j++;
		}
	}
	while (i <= n) {
		sum = (sum + (a[i] - b[m - 1]) * (n - i)) % mod;
		i++;
	}
	while (j <= m) {
		sum = (sum + (b[j] - a[n - 1]) * (m - j)) % mod;
		j++;
	}
	cout << sum << endl;
	return 0;
}