Submission #159373

#	Time	Username	Problem	Language	Result	Execution time	Memory
159373		sofhiasouza	Evacuation plan (IZhO18_plan)	C++14	100 / 100	1057 ms	21880 KiB

plan

#include <bits/stdc++.h>
#define pb push_back
#define F first
#define S second
using namespace std;
typedef pair < int, int > ii;

const int maxn = 1e5+10, inf = 0x3f3f3f3f;

int n, m, k, q, pai[maxn], peso[maxn], resp[maxn], vist[maxn], cont, nivel[maxn];
ii dist[maxn];

bool npp[maxn];

vector < ii > grafo[maxn];

void dijkstra()
{
	priority_queue < int, vector < int >, greater < int > > fila;

	for(int i = 1 ; i <= n ; i++)
	{
		if(npp[i])
		{
			fila.push(i);
			dist[i] = {0, i};
		}
		else dist[i] = {inf, i};
	}	

	while(fila.size())
	{
		int u = fila.top();
		fila.pop();

		for(ii k : grafo[u])
		{
			int v = k.F;
			int cst = k.S;

			if(dist[v].F > dist[u].F + cst)
			{
				fila.push(v);
				dist[v].F = dist[u].F + cst; 
			}
		}
	}
}

bool cmp(ii a, ii b)
{
	return a.F > b.F;
}

int find(int x)
{
	if(pai[x] == x) return x;
	return find(pai[x]);
}

void join(int u, int v)
{
	u = find(u);
	v = find(v);

	if(u == v) return;

	if(peso[u] < peso[v]) swap(u, v);

	pai[v] = u, peso[u] += peso[v], resp[v] = cont;
}

void dfs(int x)
{
	vist[x] = 1;
	if(pai[x] == x)
	{
		nivel[x] = 0;
		return;
	}
	if(!vist[pai[x]]) dfs(pai[x]);
	nivel[x] = nivel[pai[x]] + 1;
}

int get(int u, int v)
{
	int ans = 0;

	while(u != v)
	{
		if(nivel[u] > nivel[v]) ans = max(ans, resp[u]), u = pai[u];
		else ans = max(ans, resp[v]), v = pai[v];
	}

	return ans;
}

int main()
{
	ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); 

	cin >> n >> m;

	for(int i = 1 ; i <= m ; i++)
	{
		int a, b, c;
		cin >> a >> b >> c;

		grafo[a].pb({b, c});
		grafo[b].pb({a, c});
	}

	memset(npp, false, sizeof npp);

	cin >> k;

	for(int i = 1 ; i <= k ; i++)
	{
		int a;
		cin >> a;

		npp[a] = true;
	}

	dijkstra();

	sort(dist+1, dist+1+n, cmp);

	for(int i = 1 ; i <= n ; i++)
	{
		pai[i] = i;
		peso[i] = 1;
		resp[i] = 1;
	}

	for(int i = 1 ; i <= n ; i++)
	{
		int u = dist[i].S;
	
		cont++;

		for(ii k : grafo[u])
		{
			int v = k.F;
			if(vist[v]) join(u, v);
		}

		vist[u] = 1;
	}	

	memset(vist, 0, sizeof vist);

	for(int i = 1 ; i <= n ; i++)
	{
		if(!vist[i]) dfs(i);
	}

	cin >> q;

	for(int i = 1 ; i <= q ; i++)
	{
		int a, b;
		cin >> a >> b;
	
		cout << dist[get(a, b)].F << "\n";
	}
}

• Subtask 1: 10 / 10
• Subtask 2: 13 / 13
• Subtask 3: 12 / 12
• Subtask 4: 19 / 19
• Subtask 5: 46 / 46