Submission #42501

#	Time	Username	Problem	Language	Result	Execution time	Memory
42501		MatheusLealV	Evacuation plan (IZhO18_plan)	C++14	100 / 100	655 ms	34952 KiB

plan

#include <bits/stdc++.h>
#define N 100005
#define inf 2000000000
#define f first
#define s second
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;

int n, m, k, q, P[N], id[N], dist[N], rev[N], pai[N], peso[N];

vector<pii> grafo[N];

list<int> l[N];

list<pii> hist[N];

void dijkstra()
{
	priority_queue<pii, vector<pii>, greater<pii> > pq;

	for(int i = 1; i <= n; i++) dist[i] = inf;

	for(int i = 1; i <= k; i++) dist[ P[i] ] = 0, pq.push({0, P[i]});

	while(!pq.empty())
	{
		int x = pq.top().s, d = pq.top().f;

		pq.pop();

		if(d > dist[x]) continue;

		for(auto v: grafo[x])
		{
			if(dist[v.f] > dist[x] + v.s)
			{
				dist[v.f] = dist[x] + v.s;

				pq.push({dist[v.f], v.f});
			}
		}
	}

	vector<pii> v;

	for(int i = 1; i <= n; i++) v.push_back({dist[i], i});

	sort(v.begin(), v.end());

	for(int i = 0; i < v.size(); i++) id[ v[i].s ] = i + 1, rev[i + 1] = v[i].s;
}

void persistent_join(int a, int b, int t)
{
	a = pai[a], b = pai[b];

	if(a != b)
	{
        if(peso[a] > peso[b]) swap(a, b);

        for(auto it = l[a].begin(); it != l[a].end(); it++)
        {
                hist[*it].push_back(pii(t, b));

                pai[*it] = b;
        }

        peso[b] += peso[a];

        l[b].splice(l[b].end(), l[a]);
	}
}

int p_query(int a, int b)
{
	int ans = 0;

	for(auto x: hist[a])
		for(auto y: hist[b])
			if(x.s == y.s)
				ans = max(ans, min(x.f, y.f));

	return ans;
}

int main()
{
	ios::sync_with_stdio(false); cin.tie(0);

	cin>>n>>m;

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

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

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

	cin>>k;

	for(int i = 1; i <= k; i++) cin>>P[i];

	dijkstra();

    for(int i = 1; i <= n; i++)
    {
        l[i].push_back(i);

        hist[i].push_back(pii(dist[i], i));

        peso[i] = 1, pai[i] = i;
    }

	for(int x = n; x >= 1; x--)
	{
		int xi = rev[x];

		for(auto v: grafo[xi])

			if(id[v.f] > x) persistent_join(v.f, xi, dist[xi]);
	}

	cin>>q;

	for(int t = 1, a, b; t <= q; t++)
	{
		cin>>a>>b;

		cout<<p_query(a, b)<<"\n";
	}
}

Compilation message (stderr)

plan.cpp: In function 'void dijkstra()':
plan.cpp:51:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < v.size(); i++) id[ v[i].s ] = i + 1, rev[i + 1] = v[i].s;
                 ~~^~~~~~~~~~

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