Submission #26545

#	Time	Username	Problem	Language	Result	Execution time	Memory
26545		rubabredwan	Factories (JOI14_factories)	C++14	15 / 100	6000 ms	236552 KiB

factories

/*  Bismillahir Rahmanir Rahim  */

#include <bits/stdc++.h>
#include "factories.h"

using namespace std;

typedef pair <int, long long> pii;

const int N = 500005;
const long long oo = 1e18;

vector <pii> g[N];
int n;
int tot;
int sub[N];
int anc[N];
int vis[N];
long long mn[N];
vector <long long> pre[N];
stack <int> rem;

void dfs0(int at, int par){
	++tot;
	sub[at] = 1;
	for(auto u : g[at]){
		if(vis[u.first] || u.first == par) continue;
		dfs0(u.first, at);
		sub[at] += sub[u.first];
	}
}

int get(int at, int par){
	for(auto u : g[at]){
		if(vis[u.first] || u.first == par) continue;
		if(sub[u.first] > tot / 2) return get(u.first, at);
	}
	return at;
}

void get_dis(int at, int par, long long dis){
	pre[at].push_back(dis);
	for(auto u : g[at]){
		if(vis[u.first] || u.first == par) continue;
		get_dis(u.first, at, dis + u.second);
	}
}

void decompose(int at, int par){
	tot = 0;
	dfs0(at, at);
	int cen = get(at, at);
	vis[cen] = 1;
	if(par) anc[cen] = par;
	get_dis(cen, cen, 0);
	for(auto u : g[cen]){
		if(vis[u.first]) continue;
		decompose(u.first, cen);
	}
}

void update(int from){
	int cur = from;
	for(auto u : pre[from]){
		mn[cur] = min(mn[cur], u);
		rem.push(cur);
		cur = anc[cur];
	}
}

long long query(int from){
	int cur = from;
	long long ret = oo;
	for(auto u : pre[from]){
		ret = min(ret, mn[cur] + u);
		cur = anc[cur];
	}
	return ret;
}

void reset(){
	while(!rem.empty()){
		mn[rem.top()] = oo;
		rem.pop();
	}
}

long long Query(int S, int X[], int T, int Y[]){
	reset();
	for(int i = 0; i < S; ++i){
		update(X[i] + 1);
	}	
	long long ret = oo;
	for(int i = 0; i < T; ++i){
		ret = min(ret, query(Y[i] + 1));
	}
	return ret;
}

void Init(int N, int A[], int B[], int D[]){
	n = N;
	for(int i = 0; i < N - 1; ++i){
		g[A[i] + 1].push_back({B[i] + 1, D[i]});
		g[B[i] + 1].push_back({A[i] + 1, D[i]});
	}
	decompose(1, 0);
	for(int i = 1; i <= n; ++i) mn[i] = oo;
	for(int i = 1; i <= n; ++i){
		reverse(pre[i].begin(), pre[i].end());
	}
}

• Subtask 1: 15 / 15
• Subtask 2: 0 / 18
• Subtask 3: 0 / 67