#include #include #include #include using namespace std; const int N = 2e5 + 10, M = N << 1; int n, du[N]; // 链式前向星 int e[M], h[N], idx, w[M], ne[M]; void add(int a, int b, int c = 0) { e[idx] = b, ne[idx] = h[a], w[idx] = c, h[a] = idx++; } int d[N], f[N]; void dfs1(int u, int fa) { for (int i = h[u]; ~i; i = ne[i]) { int v = e[i]; if (v == fa) continue; dfs1(v, u); if (du[v] == 1) d[u] += w[i]; else d[u] += min(d[v], w[i]); } return; } void dfs2(int u, int fa) { for (int i = h[u]; ~i; i = ne[i]) { int v = e[i]; if (v == fa) continue; if (du[u] == 1) f[v] = d[v] + w[i]; else f[v] = d[v] + min(f[u] - min(d[v], w[i]), w[i]); dfs2(v, u); } return; } int main() { // 加快读入 ios::sync_with_stdio(false), cin.tie(0); int T; cin >> T; while (T--) { // 初始化链式前向星 memset(h, -1, sizeof h); idx = 0; memset(du, 0, sizeof du); memset(d, 0, sizeof d); memset(f, 0, sizeof f); cin >> n; int a, b, c; for (int i = 1; i < n; i++) { // 树,n-1条无向边 cin >> a >> b >> c; add(a, b, c), add(b, a, c); du[a]++, du[b]++; // 记录入度,无向图就不谈入度和出度了 } dfs1(1, 0); f[1] = d[1]; dfs2(1, 0); int ans = 0; for (int i = 1; i <= n; i++) ans = max(ans, f[i]); cout << ans << endl; } return 0; }