本来已经按自己的回溯做出来了，下面这个是老师的做法，感觉老师的思路不对，求大佬帮我改改

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

int t[5],a[65],ans,sum,now,y,maxtime,maxdeep;
void dfs(int x)
{
	if(x>maxdeep) {
		maxtime=max(maxtime,sum-now);
		cout<<"now:"<<now<<endl;
		return ;
	}
	if(now+a[x]<=sum/2) {
		now+=a[x];
		cout<<"now+:"<<now<<endl;
		dfs(x+1);
		now-=a[x];
	}
	dfs(x+1);
}

int main()
{
	for(int i=1;i<=4;i++) {
		cin >> t[i];
	}
	
	for(int i=1;i<=4;i++)
	{
		memset(a,0,sizeof(a));
		sum=0;now=0;
		for(int j=1;j<=t[i];j++)
		{
			cin>>a[j];
			sum+=a[j];
		}
		maxdeep=t[i];
		maxtime=0;
		dfs(1);
		ans+=maxtime;
		cout<<"maxtime:"<<maxtime<<" now:"<<now<<endl;
	}
	cout << ans;
	return 0;
}