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| #include <bits/stdc++.h>
using namespace std;
int n, i, u, v, w, head[100002], cnt = 1, cnt01 = 1, ch[100002 * 32][2], ans, sum[100002];
struct Edge{
int to, next, w;
}e[100002 << 1];
void addEdge(int from, int to, int ww) {
e[cnt].to = to;
e[cnt].w = ww;
e[cnt].next = head[from];
head[from] = cnt++;
}
void addWt(int x) {
bool m;
for (int k = 31, s = 0; k >= 0; --k) {
m = x & (1 << k);
if (!ch[s][m]) {
ch[s][m] = cnt01++;
}
s = ch[s][m];
}
}
void dfs(int p, int fa, int xorw) {
sum[p] = xorw;
addWt(xorw);
for (int k = head[p]; k; k = e[k].next) {
if (e[k].to != fa) {
dfs(e[k].to, p, xorw ^ e[k].w);
}
}
}
void find(int x) {
bool m;
int nans = 0;
for (int k = 31, s = 0; k >= 0; --k) {
m = x & (1 << k);
if (ch[s][!m]) {
nans <<= 1;
++nans;
s = ch[s][!m];
}
else {
nans <<= 1;
s = ch[s][m];
}
}
ans = max(ans, nans);
}
int main() {
cin >> n;
for (i = 1; i < n; ++i) {
cin >> u >> v >> w;
addEdge(u, v, w);
addEdge(v, u, w);
}
dfs(1, 0, 0);
for (i = 2; i <= n; ++i) {
find(sum[i]);
}
cout << ans << endl;
}
|