Submission #113517

#	Time	Username	Problem	Language	Result	Execution time	Memory
113517		AngusRitossa	Factories (JOI14_factories)	C++14	100 / 100	4864 ms	217540 KiB

factories

#include "factories.h"
#include <bits/stdc++.h>
using namespace std;
#ifdef DEBUG
	#define D(x...) printf(x)
#else
	#define D(x...)
#endif
typedef long long ll;
int n;
vector<pair<int, int> > adj[500000];
int iscentroid[500000];
int sz[500000];
ll closest[500000];
pair<int, ll> mycentroids[500000][19];
int findsz(int a, int p = -1)
{
	sz[a] = 1;
	for (auto b : adj[a])
	{
		if (b.first != p && !iscentroid[b.first]) sz[a] += findsz(b.first, a);
	}
	return sz[a];
}	
ll len = 0;
void dfslen(int a, int c, int p = -1, ll len = 0)
{
	mycentroids[a][iscentroid[c]-1] = { c, len };
	D("%d belongs to %d, dis %lld\n", a, c, len);
	for (auto b : adj[a])
	{
		if (!iscentroid[b.first] && b.first != p)
		{
			dfslen(b.first, c, a, len+b.second);
		}
	}
}
void findcentroid(int a, int upto = 1, int above = 0, int p = -1)
{
	int sumchildren = above+1;
	pair<int, int> mxchild = { 0, 0 };
	for (auto b : adj[a])
	{
		if (b.first != p && !iscentroid[b.first])
		{
			mxchild = max(mxchild, { sz[b.first], b.first } );
			sumchildren += sz[b.first];
		}
	}
	if (mxchild.first <= (sumchildren)/2)
	{
		// is a centroid
		iscentroid[a] = upto;
		dfslen(a, a);
		if (p != -1 && !iscentroid[p]) findsz(p, a);
		for (auto b : adj[a])
		{
			if (!iscentroid[b.first]) findcentroid(b.first, upto+1);
		}
		return;
	}
	findcentroid(mxchild.second, upto, sumchildren-mxchild.first, a);
}
 
void Init(int N, int A[], int B[], int D[]) 
{
	n = N;
	for (int i = 0; i < n-1; i++)
	{
		adj[A[i]].emplace_back(B[i], D[i]);
		adj[B[i]].emplace_back(A[i], D[i]);
	}
	for (int i = 0; i < n; i++) fill_n(mycentroids[i], 19, make_pair(0, 1e15));
	findsz(0);
	findcentroid(0);
	fill_n(closest, n, 1e15);
}
ll Query(int s, int x[], int t, int y[]) 
{
	ll ans = 1e15;
	for (int i = 0; i < s; i++) for (int j = 0; j < 19; j++) 
	{
		closest[mycentroids[x[i]][j].first] = min(closest[mycentroids[x[i]][j].first], mycentroids[x[i]][j].second);
	}
	for (int i = 0; i < t; i++) for (int j = 0; j < 19; j++) 
	{
		ans = min(ans, closest[mycentroids[y[i]][j].first]+mycentroids[y[i]][j].second);
	}
	for (int i = 0; i < s; i++) for (int j = 0; j < 19; j++) 
	{
		closest[mycentroids[x[i]][j].first] = 1e15;
	}
	return ans;
}

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