Submission #146265

#	Time	Username	Problem	Language	Result	Execution time	Memory
146265		jwvg0425	Split the Attractions (IOI19_split)	C++17	40 / 100	177 ms	23952 KiB

split

#include "split.h"
#include <stdio.h>
#include <vector>
#include <queue>
#include <algorithm>
#include <iostream>
#include <string>
#include <bitset>
#include <map>
#include <set>
#include <tuple>
#include <string.h>
#include <math.h>
#include <random>
#include <functional>
#include <assert.h>
#include <math.h>
#define all(x) (x).begin(), (x).end()
#define xx first
#define yy second

using namespace std;

using i64 = long long int;
using ii = pair<int, int>;
using ii64 = pair<i64, i64>;

vector<int> edge[100005];
vector<int> treeEdge[100005];
bool visited[100005];
int cent;
int val[100005];
int csize[100005];
int treeNum[100005];
int parent[100005];
int treeSize[100005];
int compSize[100005];
bool usingTree[100005];
int usingSize;

void dfs(int root)
{
	visited[root] = true;

	for (auto& e : edge[root])
	{
		if (visited[e])
			continue;

		treeEdge[root].push_back(e);
		treeEdge[e].push_back(root);

		dfs(e);
	}
}

int findCent(int root, int n)
{
	csize[root] = 1;

	bool isCent = true;

	for (auto& e : treeEdge[root])
	{
		if (e == parent[root])
			continue;

		parent[e] = root;
		int c = findCent(e, n);

		if (c != -1)
			return c;

		csize[root] += csize[e];

		isCent = isCent && (csize[e] <= (n + 1) / 2);
	}

	if (isCent && n - csize[root] <= (n + 1) / 2)
		return root;

	return -1;
}

int treeDfs(int root, int k)
{
	// cent 방향 안 가면서 크기 계산, 트리 번호도 붙여준다
	int res = 1;
	visited[root] = true;
	treeNum[root] = k;

	for (auto& e : treeEdge[root])
	{
		if (treeNum[e] != 0 || e == cent)
			continue;

		res += treeDfs(e, k);
	}

	return res;
}

int comp(int root)
{
	int res = 0;
	if (!usingTree[treeNum[root]])
	{
		res += treeSize[treeNum[root]];
		usingTree[treeNum[root]] = true;
	}
	visited[root] = true;

	for (auto& e : edge[root])
	{
		if (visited[e] || e == cent)
			continue;

		res += comp(e);
	}

	return res;
}

void findTree(int root, int sz)
{
	if (usingSize >= sz)
		return;

	if (!usingTree[treeNum[root]])
	{
		usingSize += treeSize[treeNum[root]];
		usingTree[treeNum[root]] = true;
	}
	visited[root] = true;


	for (auto& e : edge[root])
	{
		if (visited[e] || e == cent)
			continue;

		findTree(e, sz);
	}
}

void mark(int root, int v, int& sz)
{
	if (sz == 0)
		return;

	val[root] = v;
	sz--;

	for (auto& e : edge[root])
	{
		if (val[e] != 0 || !usingTree[treeNum[e]])
			continue;

		mark(e, v, sz);
	}
}

void mark2(int root, int v, int& sz)
{
	if (sz == 0)
		return;
	
	val[root] = v;
	sz--;

	for (auto& e : edge[root])
	{
		if (val[e] != 0)
			continue;

		mark2(e, v, sz);
	}
}

vector<int> find_split(int n, int a, int b, int c, vector<int> p, vector<int> q)
{
	vector<ii> v = { { a, 1 }, { b, 2 }, { c, 3 } };

	for (int i = 0; i < p.size(); i++)
	{
		edge[p[i]].push_back(q[i]);
		edge[q[i]].push_back(p[i]);
	}

	dfs(0);

	sort(all(v));

	cent = findCent(0, n);

	// centroid 제외한 그래프에서 a이상의 크기인 트리가 있는지 확인, 있으면 go
	int tr = 1;
	for (auto& e : edge[cent])
	{
		treeSize[tr] = treeDfs(e, tr);
		if (treeSize[tr] >= v[0].xx)
		{
			//이 경우, 얘 하나만 써도 OK
			usingTree[tr] = true;
			mark(e, v[0].yy, v[0].xx);
			mark2(cent, v[1].yy, v[1].xx);

			for (int i = 0; i < n; i++)
				if (val[i] == 0)
					val[i] = v[2].yy;

			vector<int> result(n);
			for (int i = 0; i < n; i++)
				result[i] = val[i];

			return result;
		}

		tr++;
	}

	memset(visited, false, sizeof(visited));
	for (auto& e : edge[cent])
	{
		int c = comp(e);

		if (c < v[0].xx)
			continue;

		// 합해서 a이상 되는 트리 확인 후, 그 트리에 속하는 원소들만 이용해서 a개수 만든다
		memset(visited, false, sizeof(visited));
		memset(usingTree, false, sizeof(usingTree));
		findTree(e, v[0].xx);

		mark(e, v[0].yy, v[0].xx);
		mark2(cent, v[1].yy, v[1].xx);

		for (int i = 0; i < n; i++)
			if (val[i] == 0)
				val[i] = v[2].yy;

		break;
	}

	vector<int> result(n);
	for (int i = 0; i < n; i++)
		result[i] = val[i];

	return result;
}

Compilation message (stderr)

split.cpp: In function 'std::vector<int> find_split(int, int, int, int, std::vector<int>, std::vector<int>)':
split.cpp:184:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < p.size(); i++)
                  ~~^~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 11 / 11
• Subtask 3: 22 / 22
• Subtask 4: 0 / 24
• Subtask 5: 0 / 36