01trie板子求调

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i, a, b) for(int i = (a); i <= (b); ++ i)
#define per(i, a, b) for(int i = (a); i >= (b); -- i)
typedef long long ll;
typedef unsigned long long ull;
const int N = 100005;
const int INF = 0x3f3f3f3f;
int n, tot, ans = -INF, tr[N << 5][2], dis[N << 5];
struct edge{ int v, w; };
vector<edge> g[N];
edge newedge(int v, int w) {
	edge tmp;
	tmp.v = v; tmp.w = w;
	return tmp;
}
void dfs(int u, int fa) {
	for(int i = 0; i < g[u].size(); ++ i) {
		int v = g[u][i].v;
		int w = g[u][i].w;
		if(v != fa) {
			dis[v] = dis[u] ^ w;
			dfs(v, u);
		}
	}
}
void insert(int x) {
	int u = 1;
	per(i, 31, 0) {
		int v = (x >> i) & 1;
		if(!tr[u][v]) tr[u][v] = ++ tot;
		u = tr[u][v];
	}
}
int query(int u) {
	int p = 1;
	int ans = 0;
	per(i, 31, 0) {
		int v = ((u >> i) & 1);
		if(tr[u][v ^ 1]) ans += (1 << i), p = tr[p][v ^ 1];
		else p = tr[p][v];
	}
	return ans;
}
void solve() {
	cin >> n; 
	rep(i, 1, n - 1) {
		int u, v, w;
		cin >> u >> v >> w; 
		g[u].push_back(newedge(v, w));
		g[v].push_back(newedge(u, w));
	}
	dfs(1, 0);
	rep(i, 1, n) insert(dis[i]);
	rep(i, 1, n) ans = max(ans, query(dis[i]));
	cout << ans << '\n';
 	return;
}
signed main() {
	ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	int T = 1;
	// cin >> T;
	while(T --) solve();
	return 0;
}