Submission #103807

#	Time	Username	Problem	Language	Result	Execution time	Memory
103807		igba	Factories (JOI14_factories)	C++17	0 / 100	19 ms	12416 KiB

factories

#include <bits/stdc++.h>
#include "factories.h"
 
using namespace std;
#define mkp make_pair
const int MAXN = 5 * 100100, MAXLN = 20;
const long long LINF = 0x3f3f3f3f3f3f3f3f;
int n, sz[MAXN], cdp[MAXN];
long long aux[MAXN], cdpd[MAXN];
bool rmd[MAXN];
vector<pair<int, int>> g[MAXN];

void szdfs(int v, int p = -1)
{
	sz[v] = 1;
	for(const auto&[w, u] : g[v])
		if(u != p && !rmd[u])
			szdfs(u, v), sz[v] += sz[u];
}

int getCentroid(int v, int p = -1, int rt = -1)
{
	if(rt == -1)
		rt = v;
	for(const auto&[w, u] : g[v])
		if(u != p && !rmd[u] && sz[u] > sz[rt] / 2)
			return getCentroid(u, v, rt);
	return v;
}

long long getDist(int v, int trgt, int p = -1)
{
	if(v == trgt)
		return 0;
	long long aux = LINF;
	for(const auto&[w, u] : g[v])
		if(u != p)
			aux = min(aux, getDist(u, trgt, v) + w);
	return aux;
}

void cd(int v, int cp = -1)
{
	szdfs(v);
	int c = getCentroid(v);
	if(cp != -1)
		cdpd[c] = getDist(c, cp);
	cdp[c] = cp, rmd[c] = true;
	for(const auto&[w, u] : g[c])
		if(!rmd[u])
			cd(u, c);
}

void Init(int N, int A[], int B[], int D[])
{
	n = N;
	for(int i = 0; i < n - 1; ++i)
		g[A[i]].push_back(mkp(D[i], B[i])), g[B[i]].push_back(mkp(D[i], A[i]));
	cd(0);
}

long long Query(int S, int X[], int T, int Y[])
{
	long long ans = LINF, d;
	for(int i = 0; i < n; ++i)
		aux[i] = LINF;
	for(int i = 0, cur; i < S; ++i)
	{
		cur = X[i], d = 0;
		while(cur != -1)
		{
			aux[cur] = min(aux[cur], d);
			d += cdpd[cur], cur = cdp[cur];
		}
	}
	for(int i = 0, cur; i < T; ++i)
	{
		cur = Y[i], d = 0;
		while(cur != -1)
		{
			ans = min(ans, aux[cur] + d);
			d += cdpd[cur], cur = cdp[cur];
		}
	}
	return ans;
}

Compilation message (stderr)

factories.cpp: In function 'void szdfs(int, int)':
factories.cpp:16:22: warning: unused variable 'w' [-Wunused-variable]
  for(const auto&[w, u] : g[v])
                      ^
factories.cpp: In function 'int getCentroid(int, int, int)':
factories.cpp:25:22: warning: unused variable 'w' [-Wunused-variable]
  for(const auto&[w, u] : g[v])
                      ^
factories.cpp: In function 'void cd(int, int)':
factories.cpp:49:22: warning: unused variable 'w' [-Wunused-variable]
  for(const auto&[w, u] : g[c])
                      ^

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