Submission #210003

#	Time	Username	Problem	Language	Result	Execution time	Memory
210003		Alexa2001	Hotspot (NOI17_hotspot)	C++17	100 / 100	666 ms	61816 KiB

hotspot

#include <bits/stdc++.h>

using namespace std;

///10:23

const int Nmax = 5005;

long double ans[Nmax];
bool used[Nmax];
vector<int> v[Nmax];

int dist[Nmax][Nmax], pos[Nmax][Nmax], A[Nmax], B[Nmax];
int n, m, k;

void doo(int node, int dist[], int pos[])
{
    int i;
    for(i=0; i<n; ++i) dist[i] = -1;

    dist[node] = 0;
    pos[node] = 1;

    queue<int> q;
    q.push(node);

    while(q.size())
    {
        node = q.front();
        q.pop();

        for(auto it : v[node])
            if(dist[it] == -1)
            {
                dist[it] = dist[node] + 1;
                pos[it] = pos[node];
                q.push(it);
            }
            else if(dist[it] == dist[node] + 1)
                pos[it] += pos[node];
    }
}

int main()
{
   // freopen("input", "r", stdin);
    cin.sync_with_stdio(false); cin.tie(0);

    cin >> n >> m;

    int i, j;
    for(i=1; i<=m; ++i)
    {
        int x, y;
        cin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }

    cin >> k;
    for(i=1; i<=k; ++i)
    {
        cin >> A[i] >> B[i];
        if(!used[A[i]]) doo(A[i], dist[A[i]], pos[A[i]]), used[A[i]] = 1;
        if(!used[B[i]]) doo(B[i], dist[B[i]], pos[B[i]]), used[B[i]] = 1;
    }

    for(i=1; i<=k; ++i)
        for(j=0; j<n; ++j)
            if(dist[A[i]][j] + dist[B[i]][j] == dist[A[i]][B[i]])
                ans[j] += (long double) pos[A[i]][j] * pos[B[i]][j] / pos[A[i]][B[i]];

    int id = 0;
    for(i=0; i<n; ++i)
        if(ans[i] > ans[id])
            id = i;
    cout << id << '\n';
    return 0;
}

• Subtask 1: 4 / 4
• Subtask 2: 5 / 5
• Subtask 3: 11 / 11
• Subtask 4: 18 / 18
• Subtask 5: 26 / 26
• Subtask 6: 36 / 36