Submission #446164

#	Time	Username	Problem	Language	Result	Execution time	Memory
446164		blue	Evacuation plan (IZhO18_plan)	C++17	100 / 100	1540 ms	48096 KiB

plan

#include <iostream>
#include <vector>
#include <set>

#include <algorithm>
using namespace std;

const int max_n = 1e5;
const int INF = 1e9;

vector<int> power_dist(1+max_n, INF);

struct city
{
    int i;
};

bool operator < (city A, city B)
{
    if(power_dist[A.i] == power_dist[B.i]) return A.i < B.i;
    return power_dist[A.i] < power_dist[B.i];
}

vector<int> merge_cc[1+max_n], merge_dist[1+max_n];

vector<int> col_set[1+max_n];
vector<int> node_col(1+max_n);

void merge(int a, int b)
{
    if(node_col[a] == node_col[b]) return;

    if(col_set[ node_col[a] ].size() < col_set[ node_col[b] ].size()) swap(a, b);

    int colA  = node_col[a];
    int colB = node_col[b];

    for(int z: col_set[colB])
    {
        node_col[z] = colA;
        col_set[colA].push_back(z);
        merge_cc[z].push_back(colA);
        merge_dist[z].push_back(min(power_dist[a], power_dist[b]));
    }
    col_set[colB].clear();

//     cerr << "merging " << a << ", " << b << " at " << min(power_dist[a], power_dist[b]) << '\n';
}

int main()
{
    int n, m;
    cin >> n >> m;

    vector<int> edge[1+n], dist[1+n];

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

        edge[a].push_back(b);
        dist[a].push_back(w);

        edge[b].push_back(a);
        dist[b].push_back(w);
    }

    int k;
    cin >> k;
    for(int p = 1; p <= k; p++)
    {
        int g;
        cin >> g;

        power_dist[g] = 0;
    }

    set<city> tbv;
    for(int i = 1; i <= n; i++) tbv.insert(city{i});

    while(!tbv.empty())
    {
        int u = tbv.begin()->i;
        tbv.erase(tbv.begin());

        for(int e = 0; e < edge[u].size(); e++)
        {
            int v = edge[u][e];
            int w = dist[u][e];

            if(power_dist[v] > power_dist[u] + w)
            {
                tbv.erase(city{v});
                power_dist[v] = power_dist[u] + w;
                tbv.insert(city{v});
            }
        }
    }

    // for(int u = 1; u <= n; u++) cerr << u << ": " << power_dist[u] << '\n';



    vector<int> power_sort(n);
    for(int i = 0; i < n; i++) power_sort[i] = i+1;
    sort(power_sort.begin(), power_sort.end(), [] (int x, int y)
    {
        return power_dist[x] > power_dist[y];
    });





    for(int i = 1; i <= n; i++)
    {
        node_col[i] = i;
        col_set[i].push_back(i);
        merge_cc[i].push_back(i);
        merge_dist[i].push_back(INF);
    }


    for(int p: power_sort)
    {
        for(int q: edge[p])
        {
            // cerr << "p = " << p << ", q = " << q << '\n';
            if(power_dist[q] >= power_dist[p])
                merge(p, q);
        }
    }


    int Q;
    cin >> Q;

    for(int q = 1; q <= Q; q++)
    {
        int s, t;
        cin >> s >> t;

        int ans = 0;

        // cerr << "s = " << s << ", t = " << t << '\n';

        for(int e1 = 0; e1 < merge_cc[s].size(); e1++)
        {
            for(int e2 = 0; e2 < merge_cc[t].size(); e2++)
            {
                // cerr << s << ' ' << e1 << ' ' << merge_cc[s][e1] << ' ' << merge_dist[s][e1] << ", ";
                // cerr << t << ' ' << e2 << ' ' << merge_cc[t][e2] << ' ' << merge_dist[t][e2] << "\n";
                if(merge_cc[s][e1] == merge_cc[t][e2])
                {
                    ans = max(ans, min(merge_dist[s][e1], merge_dist[t][e2]));
                }
            }
        }

        cout << ans << '\n';
    }
}

Compilation message (stderr)

plan.cpp: In function 'int main()':
plan.cpp:87:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   87 |         for(int e = 0; e < edge[u].size(); e++)
      |                        ~~^~~~~~~~~~~~~~~~
plan.cpp:148:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  148 |         for(int e1 = 0; e1 < merge_cc[s].size(); e1++)
      |                         ~~~^~~~~~~~~~~~~~~~~~~~
plan.cpp:150:32: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  150 |             for(int e2 = 0; e2 < merge_cc[t].size(); e2++)
      |                             ~~~^~~~~~~~~~~~~~~~~~~~

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