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Two implementations for JOI factories
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‎.vscode/launch.json

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{
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// Use IntelliSense to learn about possible attributes.
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// Hover to view descriptions of existing attributes.
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// For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
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"version": "0.2.0",
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"configurations": [
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{
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"name": "g++.exe - Build and debug active file",
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"type": "cppdbg",
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"request": "launch",
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"program": "${fileDirname}\\${fileBasenameNoExtension}.exe",
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"args": [],
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"stopAtEntry": false,
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"cwd": "C:\\MinGW\\bin",
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"environment": [],
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"externalConsole": false,
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"MIMode": "gdb",
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"miDebuggerPath": "C:\\MinGW\\bin\\gdb.exe",
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"setupCommands": [
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{
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"description": "Enable pretty-printing for gdb",
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"text": "-enable-pretty-printing",
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"ignoreFailures": true
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}
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],
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"preLaunchTask": "C/C++: g++.exe build active file"
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}
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]
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}

‎.vscode/settings.json

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{
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"files.associations": {
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"string": "cpp",
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"chrono": "cpp",
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"random": "cpp",
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"limits": "cpp",
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"valarray": "cpp"
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}
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}

‎.vscode/tasks.json

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{
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"tasks": [
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{
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"type": "cppbuild",
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"label": "C/C++: g++.exe build active file",
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"command": "C:\\MinGW\\bin\\g++.exe",
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"args": [
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"-g",
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"${file}",
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"-o",
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"${fileDirname}\\${fileBasenameNoExtension}.exe"
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],
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"options": {
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"cwd": "C:\\MinGW\\bin"
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},
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"problemMatcher": [
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"$gcc"
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],
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},
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"detail": "Task generated by Debugger."
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],
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"version": "2.0.0"
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}

‎Balkan/.vscode/settings.json

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{
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"files.associations": {
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"*.tcc": "cpp",
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"array": "cpp",
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"memory": "cpp",
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"future": "cpp",
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"istream": "cpp",
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"functional": "cpp",
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"tuple": "cpp",
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"utility": "cpp",
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"variant": "cpp"
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}
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}

‎JOI/JOI 14-factories.cpp renamed to ‎JOI/JOI 14-factories/centroid decomposition.cpp

File renamed without changes.

‎JOI/JOI 14-factories/virtual tree.cpp

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/*
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JOI 2014 Factories
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- If there were very few queries, then we can do a simple tree DP to find min(dist to X + dist to Y) from each node
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- Notice however that the only "important" nodes we need to check are on the virtual tree from (X union Y)
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- We can thus construct the virtual tree for each query and then do tree DP on it to answer the query
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- Complexity: O(V log N) where V = sum(S + T)
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*/
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#include "factories.h"
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#include <bits/stdc++.h>
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typedef long long ll;
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using namespace std;
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const ll INF = 1e18;
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vector<pair<int, ll>> graph[500000], vtree[500000];
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int tin[500000], tout[500000], timer = 0, anc[500000][19];
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ll to_anc[500000][19], to_X[500000], to_Y[500000];
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void lca_dfs(int node = 0, int parent = -1) {
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tin[node] = timer++;
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for (int i = 1; i < 19; i++) {
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anc[node][i] = anc[anc[node][i - 1]][i - 1];
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to_anc[node][i] = to_anc[node][i - 1] + to_anc[anc[node][i - 1]][i - 1];
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}
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for (pair<int, ll> i : graph[node]) if (i.first != parent) {
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anc[i.first][0] = node;
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to_anc[i.first][0] = i.second;
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lca_dfs(i.first, node);
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}
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tout[node] = timer++;
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}
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inline bool is_ancestor(int u, int v) { return (tin[u] <= tin[v] && tout[u] >= tout[v]); }
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int lca(int u, int v) {
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if (is_ancestor(u, v)) return u;
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for (int i = 18; ~i; i--) if (!is_ancestor(anc[u][i], v)) u = anc[u][i];
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return anc[u][0];
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}
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ll dist(int u, int v) {
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ll ans = 0;
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for (int i = 18; ~i; i--) if (!is_ancestor(anc[u][i], v)) {
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ans += to_anc[u][i];
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u = anc[u][i];
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}
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if (!is_ancestor(u, v)) ans += to_anc[u][0];
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for (int i = 18; ~i; i--) if (!is_ancestor(anc[v][i], u)) {
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ans += to_anc[v][i];
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v = anc[v][i];
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}
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if (!is_ancestor(v, u)) ans += to_anc[v][0];
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return ans;
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}
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void Init(int N, int A[], int B[], int D[]) {
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for (int i = 0; i < N - 1; i++) {
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graph[A[i]].push_back({B[i], D[i]});
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graph[B[i]].push_back({A[i], D[i]});
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}
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lca_dfs();
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memset(to_X, 0x3f, sizeof to_X); memset(to_Y, 0x3f, sizeof to_Y);
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}
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bool cmp(int u, int v) { return tin[u] < tin[v]; }
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ll ans;
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void dfs1(int node, int parent = 0) {
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for (pair<int, ll> i : vtree[node]) if (i.first != parent) {
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dfs1(i.first, node);
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to_X[node] = min(to_X[node], to_X[i.first] + i.second);
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to_Y[node] = min(to_Y[node], to_Y[i.first] + i.second);
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}
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}
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void dfs2(int node, int parent = 0, ll par_to_X = INF, ll par_to_Y = INF) {
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to_X[node] = min(to_X[node], par_to_X);
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to_Y[node] = min(to_Y[node], par_to_Y);
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ans = min(ans, to_X[node] + to_Y[node]);
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for (pair<int, ll> i : vtree[node]) if (i.first != parent) {
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ll nxt_par_to_X = i.second + min(par_to_X, to_X[node]);
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ll nxt_par_to_Y = i.second + min(par_to_Y, to_Y[node]);
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dfs2(i.first, node, nxt_par_to_X, nxt_par_to_Y);
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}
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}
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ll Query(int S, int X[], int T, int Y[]) {
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vector<int> nodes;
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for (int i = 0; i < S; i++) {
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to_X[X[i]] = 0;
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nodes.push_back(X[i]);
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}
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for (int i = 0; i < T; i++) {
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to_Y[Y[i]] = 0;
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nodes.push_back(Y[i]);
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}
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sort(nodes.begin(), nodes.end(), cmp);
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for (int i = 1; i < S + T; i++) nodes.push_back(lca(nodes[i - 1], nodes[i]));
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sort(nodes.begin(), nodes.end(), cmp);
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nodes.erase(unique(nodes.begin(), nodes.end()), nodes.end());
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vector<int> stck;
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for (int i : nodes) {
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while (stck.size() > 1 && !is_ancestor(stck.back(), i)) {
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int u = stck[stck.size() - 2], v = stck.back();
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vtree[u].push_back({v, dist(u, v)});
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stck.pop_back();
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}
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stck.push_back(i);
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}
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while (stck.size() > 1) {
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int u = stck[stck.size() - 2], v = stck.back();
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vtree[u].push_back({v, dist(u, v)});
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stck.pop_back();
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}
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ans = LLONG_MAX;
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dfs1(stck[0]);
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dfs2(stck[0]);
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for (int i : nodes) {
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to_X[i] = to_Y[i] = INF;
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vtree[i].clear();
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}
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return ans;
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}

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