func_code_string: #include <bits/stdc++.h>      using namespace std;      typedef long long ll;   typedef pair<int, int> pll;      #define all(x)                      (x).begin(),(x).end()   #define X                           first   #define Y                           second   #define sep                               #define endl                          n    #define debug(x)                    cerr << #x <<  :   <<  x << endl;      const ll MAXN = 1e6 + 10;   const ll INF = 8e18;   const ll MOD = 1e9 + 7; // 998244353; // 1e9 + 9;   const ll LOG = 20;      int n, m, P[MAXN], H[MAXN], t_0, par[MAXN][LOG];    vector<int> adj[MAXN];   vector<pll> adj2[MAXN];   vector<pair<int, pll>> edges, mst_edges;   set<int> un_vis;   ll ans;   bool w_0[MAXN][LOG];   set<pll> used;      int Find(int v) {    if (v == P[v]) return v;    return P[v] = Find(P[v]);   }      inline bool Union(int v, int u, int w) {    int pu = u, pv = v;    v = Find(v), u = Find(u);    if (v == u) return false;    P[v] = u;    ans += w;    used.insert({pv, pu});    used.insert({pu, pv});       if (w == 0) t_0++;    mst_edges.push_back({w, {pu, pv}});    return true;   }      void dfs(int v) {    un_vis.erase(v);        int lst = 0;    while (true) {     auto it = un_vis.upper_bound(lst);     if (it == un_vis.end()) break;     lst = *it;     if (binary_search(all(adj[v]), lst)) continue; //        Union(v, lst, 0);     dfs(lst);    }   }      void dfs2(int v, int p, int w) {    par[v][0] = p;    w_0[v][0] = (w == 0);       for (pll e : adj2[v]) {     int u = e.X, w = e.Y;     if (u == p) continue;     H[u] = H[v] + 1;     dfs2(u, v, w);    }   }      pair<int, bool> kth_par(int v, int k) {    bool b = false;    for (int i = LOG - 1; i >= 0; i--)     if (k & (1 << i))      b |= w_0[v][i], v = par[v][i];    return {v, b};   }      bool LCA(int u, int v) {    if (H[v] < H[u]) swap(v, u);    pair<int, bool> p = kth_par(v, H[v] - H[u]);    v = p.X;    bool b = p.Y;    if (v == u) return b;       for (int i = LOG - 1; i >= 0; i--) {     if (par[v][i] != par[u][i]) {      b |= w_0[v][i];      b |= w_0[u][i];      v = par[v][i];      u = par[u][i];     }    }        b |= w_0[v][0];    b |= w_0[u][0];    return b;         }      int main() {    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);    cin >> n >> m;    int x = 0;       for (int i = 0; i < m; i++) {     int u, v, w;     cin >> u >> v >> w;     x ^= w;     edges.push_back({w, {u, v}});     adj[v].push_back(u);     adj[u].push_back(v);    }       for (int i = 1; i <= n; i++) {     sort(all(adj[i]));     un_vis.insert(i);     P[i] = i;     }        while (!un_vis.empty()) dfs(*un_vis.begin());       sort(all(edges));    for (auto e : edges) Union(e.Y.X, e.Y.Y, e.X);     for (auto e : mst_edges) {     adj2[e.Y.X].push_back({e.Y.Y, e.X});     adj2[e.Y.Y].push_back({e.Y.X, e.X});    }       dfs2(1, 0, 1);    for (int i = 1; i < LOG; i++) {     for (int v = 1; v <= n; v++) {      par[v][i] = par[par[v][i - 1]][i - 1];      w_0[v][i] = w_0[v][i - 1] | w_0[par[v][i - 1]][i - 1];     }    }       ll tot = 1ll * n * (n - 1) / 2 - m;    if (tot == t_0) {     for (pair<int, pll> et : edges) {      pll e = et.Y;      if (used.find(e) != used.end()) continue;      bool b = LCA(e.X, e.Y);      if (b) return cout << min(ans + et.X, ans + x) << endl, 0;     }          cout << ans + x << endl;     return 0;     }        cout << ans << endl;    return 0;   }   