Two Set Game

// E SJH
#include<bits/stdc++.h>
#define INT long long
#define pii pair<int, int>
#define x first
#define y second
#define inf INT_MAX
#define INF LONG_LONG_MAX
#define VI vector<int>
using namespace std;
const int NN = 6e5 + 100;
INT a[NN], b[NN], chk[NN], n, m, k, dp[NN];
INT pre[NN], suf_max[NN], suf_min[NN];
char s[NN];
INT ans1[NN], ans2[NN];
INT calc(){
	INT ans = 0;
	for(int i = 1; i <= n + m; i++){
		int num;
		if(i <= m) num = b[i];
		else num = a[i - m];
		if(i & 1) ans += num;
		else ans -= num;;
	}
	return ans;
}
int main(){
#ifndef ONLINE_JUDGE
	freopen("in.in", "r", stdin);
	freopen("out.out", "w", stdout);
#endif
	int T;
	cin >> T;
	while(T--){
		cin >> n >> m;
		for(int i = 1; i <= n; i++) scanf("%d", &a[i]);
		for(int i = 1; i <= m; i++) scanf("%d", &b[i]);
		if(!(n & 1)){
			INT ans = calc();
			printf("%lld\n", ans);
			continue;
		}
		INT val = 0;
		for(int i = 2; i <= n; i++){
			if(i & 1) val += a[i];
			else val -= a[i];
		}
		INT sum0 = 0, sum1 = 0, cur_sum0 = 0, cur_sum1 = 0;
		for(int i = 1; i <= m; i += 2) sum0 += b[i];
		for(int i = 2; i <= m; i += 2) sum1 += b[i];
		for(int i = 1; i <= m; i++){
			INT tmp;
			if((m - i) & 1) tmp = val;
			else tmp = -val;

			if(i & 1){
				pre[i] = cur_sum0 - cur_sum1 + a[1] - sum0 + sum1 + tmp;
			}else{
				pre[i] = cur_sum0 - cur_sum1 - a[1] - sum0 + sum1 - tmp; 
			}
			if(i & 1){
				sum0 -= b[i];
				cur_sum0 += b[i];
			}else{
				sum1 -= b[i];
				cur_sum1 += b[i];
			}
		}
		pre[m + 1] = calc();
//		for(int i = 1; i <= m + 1; i++) cerr<<pre[i]<<" ";
		ans1[m + 2] = inf;
		ans2[m + 2] = -inf;
		for(int i = m + 1; i >= 1; i--){
			ans1[i] = max(pre[i], ans2[i + 1]);
			ans2[i] = min(pre[i], ans1[i + 1]);
//			cerr<<ans1[i]<<" "<<ans2[i]<<endl;
		}
		printf("%lld\n", ans1[1]);
	}
}