mirror of
https://git.sb/baoshuo/OI-codes.git
synced 2024-12-25 20:32:11 +00:00
178 lines
3.3 KiB
C++
178 lines
3.3 KiB
C++
#include <iostream>
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#include <algorithm>
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#include <cmath>
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#include <tuple>
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#include <utility>
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#include <vector>
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using std::cin;
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using std::cout;
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const char endl = '\n';
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const int N = 3e4 + 5;
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int n, t, c, tot, id[N], siz[N], dis[N << 1], pos[N << 1], ans[N << 1];
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std::vector<std::pair<int, int>> g[N];
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std::tuple<int, int, int> qs[N << 1];
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int tr[N * 30][2], cnt[N * 30];
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void insert(int x) {
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static int tot = 1;
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int p = 1;
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for (int i = 30; i >= 0; i--) {
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bool ch = (x >> i) & 1;
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if (!tr[p][ch]) {
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tr[p][ch] = ++tot;
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}
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p = tr[p][ch];
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cnt[p]++;
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}
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}
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int query(int x) {
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int p = 1;
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int res = 0;
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for (int i = 30; i >= 0; i--) {
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int ch = (x >> i) & 1;
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if (cnt[tr[p][ch ^ 1]]) {
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res |= 1 << i;
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p = tr[p][ch ^ 1];
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} else {
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p = tr[p][ch];
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}
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}
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return res;
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}
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void remove(int x) {
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int p = 1;
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for (int i = 30; i >= 0; i--) {
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int ch = (x >> i) & 1;
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p = tr[p][ch];
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cnt[p]--;
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}
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}
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void dfs(int u, int f, int w) {
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static int cnt = 0;
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id[u] = ++cnt;
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siz[u] = 1;
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dis[id[u]] = dis[id[f]] ^ w;
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std::for_each(g[u].rbegin(), g[u].rend(), [&](auto e) {
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int v = e.first,
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w = e.second;
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if (v == f) return;
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dfs(v, u, w);
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siz[u] += siz[v];
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});
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}
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int calc(int l, int r) {
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int res = 0;
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for (int i = l; i <= r; i++) {
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res = std::max(res, query(dis[i]));
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insert(dis[i]);
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}
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for (int i = l; i <= r; i++) {
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remove(dis[i]);
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}
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return res;
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}
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int main() {
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std::ios::sync_with_stdio(false);
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cin.tie(nullptr);
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cin >> n;
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for (int i = 1, x, y, w; i < n; i++) {
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cin >> x >> y >> w;
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g[x].emplace_back(y, w);
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g[y].emplace_back(x, w);
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}
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dfs(1, 0, 0);
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for (int i = 2; i <= n; i++) {
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qs[++tot] = {id[i], id[i] + siz[i] - 1, i};
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qs[++tot] = {id[i] + siz[i], id[i] + n - 1, i};
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}
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std::copy_n(dis + 1, n, dis + 1 + n);
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n <<= 1;
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t = std::sqrt(n);
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for (int i = 1; i <= n; i++) {
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pos[i] = (i - 1) / t + 1;
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}
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std::sort(qs + 1, qs + tot + 1, [&](auto lhs, auto rhs) -> bool {
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int p = pos[std::get<0>(lhs)],
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q = pos[std::get<0>(rhs)];
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int x = std::get<1>(lhs),
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y = std::get<1>(rhs);
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return p == q ? x < y : p < q;
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});
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for (int i = 1, p = 1; i <= pos[n]; i++) {
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int r = std::min(i * t, n),
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x = r + 1,
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y = r,
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res = 0;
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for (; pos[std::get<0>(qs[p])] == i; p++) {
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int ql, qr, id;
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std::tie(ql, qr, id) = qs[p];
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if (pos[qr] == i) {
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ans[id] += calc(ql, qr);
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continue;
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}
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while (y < qr) {
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res = std::max(res, query(dis[++y]));
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insert(dis[y]);
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}
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int tmp = res;
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while (x > ql) {
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res = std::max(res, query(dis[--x]));
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insert(dis[x]);
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}
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while (x <= r) remove(dis[x++]);
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ans[id] += res;
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res = tmp;
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}
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while (y > r) remove(dis[y--]);
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}
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cout << *std::max_element(ans + 1, ans + 1 + n) << endl;
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return 0;
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}
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