输入:

4 6
1 2 10
2 3 20
3 4 30
4 1 40
1 3 50
2 4 60

输出:

150

邻接矩阵：
代码如下:

#include <iostream>
using namespace std;int ans = -1;
const int N = 25;
int mp[N][N];
bool vis[N];
int n, m;
void dfs(int u, int sum) {ans = max(ans, sum);for (int i = 1; i <= n; i++) {if (mp[u][i] > 0 && !vis[i]) {vis[i] = true;dfs(i, sum + mp[u][i]);vis[i] = false;}}
}int main() {cin >> n >> m;for (int i  = 1; i <= m; i++) {int a, b, c;cin >> a >> b >> c;mp[a][b] = c;mp[b][a] = c;}for (int i  = 1; i <= n; i++) {vis[i] = true;dfs(i, 0);vis[i] = false;}cout << ans << endl;return 0;
}

邻接表:
代码如下:

#include <iostream>
#include <vector>
using namespace std;
const int N = 25;struct node {int from;int to;int w;
};
int ans;
bool vis[N];
vector<node>v[N];void dfs(int u, int sum) {ans = max(ans, sum);for (int i  = 0; i < v[u].size(); i++) {if (!vis[v[u][i].to] && v[u][i].w > 0) {vis[v[u][i].to] = true;dfs(v[u][i].to, sum + v[u][i].w);vis[v[u][i].to] = false;}}
}int main() {int n, m;cin >> n >> m;for (int i  = 1; i <= m; i++) {int a, b, c;cin >> a >> b >> c;v[a].push_back({a, b, c});v[b].push_back({b, a, c});}for (int i  = 1; i <= n; i++) {vis[i] = true;dfs(i, 0);vis[i] = false;}cout << ans << endl;return 0;
}