求调

#include <bits/stdc++.h>
using namespace std;
int n,m;
int a[21][21],vis[21],maxx;
int dfs(int x,int sum){
    maxx=max(maxx,sum);
	vis[x]=1;
	for(int i=1;i<=n;i++){
		if(a[x][i]==0) continue;
		if(vis[i]) continue;
		vis[i]=1;
		dfs(i,sum+a[x][i]);
		vis[i]=0;}
	vis[x]=0;
}
int main(){
	cin>>n>>m;
	for(int i=1;i<=m;i++){
		int x,y,z;
		cin>>x>>y>>z;
		a[x][y]=a[y][x]=z;}
	for(int i=1;i<=n;i++){
		vis[i]=1;
		dfs(i,0);
		vis[i]=0;}
	cout<<maxx;
}