代码
/*
* Project: 0x16_Trie
* File Created:Friday, January 8th 2021, 5:32:55 am
* Author: Bug-Free
* Problem:AcWing 144. 最长异或值路径
*/
#include <algorithm>
#include <cstring>
#include <iostream>
using namespace std;
const int N = 1e5 + 10, M = 2e5 + 10;
const int SIZE = 3e6 + 10;
int n;
int h[N], e[M], c[M], ne[M], cnt;
int a[N], son[SIZE][2], idx;
void add(int u, int v, int w) {
e[cnt] = v, c[cnt] = w, ne[cnt] = h[u], h[u] = cnt++;
}
void dfs(int u, int father, int sum) {
a[u] = sum;
for (int i = h[u]; ~i; i = ne[i]) {
int j = e[i];
if (j != father) {
dfs(j, u, sum ^ c[i]);
}
}
}
void insert(int x) {
int p = 0;
for (int i = 30; i >= 0; i--) {
int& s = son[p][x >> i & 1];
if (!s) {
s = ++idx;
}
p = s;
}
}
int query(int x) {
int p = 0, res = 0;
for (int i = 30; i >= 0; i--) {
int s = x >> i & 1;
if (son[p][!s]) {
res += 1 << i;
p = son[p][!s];
} else {
p = son[p][s];
}
}
return res;
}
int main() {
memset(h, -1, sizeof h);
cin >> n;
for (int i = 0; i < n - 1; i++) {
int u, v, w;
cin >> u >> v >> w;
add(u, v, w);
add(v, u, w);
}
dfs(0, -1, 0);
for (int i = 0; i < n; i++) {
insert(a[i]);
}
int res = 0;
for (int i = 0; i < n; i++) {
res = max(res, query(a[i]));
}
cout << res << endl;
return 0;
}
MLE了