奇妙的剪枝

#include<bits/stdc++.h>
using namespace std;
#define ioio ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define debug(x) cout<<#x<<":"<<x<<endl;
#define endl "\n"
#define P pair
#define P1 first
#define P2 second
#define p_queue priority_queue
#define u_map unordered_map
typedef long long ll;
const double eps=1e-6;
const int mod=1e9+7;
const int INF=0x3f3f3f3f;
const int N=1e5+7;
int dx[]={0,0,1,-1},dy[]={1,-1,0,0};
/*------------------------------------------*/

int n,m;
int a[N];
int flag,cnt;
vector<vector<int> >ma(21);
void dfs(int u);

void dfs_a(int x,int u,int len){
	if(x>=len-1){
		dfs(u+1);
		return ;
	}
	ma[u+1].push_back(ma[u][x]+ma[u][x+1]);
	dfs_a(x+1,u,len);
	ma[u+1].pop_back();
	ma[u+1].push_back(ma[u][x]-ma[u][x+1]);
	dfs_a(x+1,u,len);
	ma[u+1].pop_back();
	ma[u+1].push_back(ma[u][x+1]-ma[u][x]);
	dfs_a(x+1,u,len);
	ma[u+1].pop_back();
}
void dfs(int u){
	cnt++;
    //cnt搜索次数足够大时，大胆认为无解了，5000000是试出来的一个比较合理的数字
	if(flag||cnt>=5000000)return ;
	int len=ma[u].size();
	if(len==1){
		if(ma[u][0]==0)flag=1;
		return ;
	}
	dfs_a(0,u,len);
}
int main(){
	ioio
	cin>>n>>m;
	for(int i=1;i<=n+m;i++){
		cin>>a[i];
		ma[1].push_back(a[i]);
	}
	dfs(1);
	if(flag)cout<<"Yes"<<endl;
	else cout<<"No"<<endl;
	return 0;
}