Submission #1165068

#	Time	Username	Problem	Language	Result	Execution time	Memory
1165068		DangKhoizzzz	Hotspot (NOI17_hotspot)	C++20	38 / 100	86 ms	21060 KiB

hotspot

// 1 / 5

#include <bits/stdc++.h>
#define int long long
#define fi first
#define se second
#define pii pair <int , int>
#define arr3 array <int , 3>

/*
+ array limit ???
+ special case ??? n = 1?
+ time limit ???
*/

using namespace std;

const int INF = 1e18 + 7;
const int maxn = 5e3 + 7;


vector <int> g[5005];
int n , k , m , f[5005][5005] , ways[5005][5005];
pii query[maxn];

void bfs(int st)
{
    for(int i = 1; i <= n; i++) f[st][i] = INF;
    f[st][st] = 0;
    ways[st][st] = 1;

    vector <bool> vis(maxn , 0);

    queue <int> Q;
    Q.push(st);

    while(!Q.empty())
    {
        int u = Q.front();
        Q.pop();

        if(vis[u]) continue;
        vis[u] = 1;

        for(int v: g[u])
        {
            if(f[st][v] > f[st][u] + 1)
            {
                f[st][v] = f[st][u] + 1;
                ways[st][v] = ways[st][u];
            }
            else if(f[st][v] == f[st][u] + 1)
            {
                ways[st][v] += ways[st][u];
            }

            if(!vis[v]) Q.push(v);
        }
    }
}

pair <double , int> ans = {-1 , -1};

void solve()
{
    cin >> n >> m;
    for(int i = 1; i <= m; i++)
    {
        int u , v; cin >> u >> v;
        u++, v++;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    for(int i = 1; i <= n; i++) {bfs(i);}
    cin >> k;
    for(int i = 1; i <= k; i++)
    {
        cin >> query[i].fi >> query[i].se;
        query[i].fi++ , query[i].se++;
    }


    for(int u = 1; u <= n; u++)
    {
        int total = 0 , sum = 0;

        for(int i = 1; i <= k; i++)
        {
            if(f[query[i].fi][u] + f[u][query[i].se] == f[query[i].fi][query[i].se])
            {
                sum += ways[query[i].fi][u] * ways[query[i].se][u];
            }
            total += ways[query[i].fi][query[i].se];
        }
        ans = max(ans , {((double)(1.0 * sum )/ total) , u});
    }
    cout << ans.se - 1 << '\n';
}

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    //freopen("inp.txt" , "r" , stdin);
    //freopen("out.txt" , "w" , stdout);
    solve();
    return 0;
}

• Subtask 1: 4 / 4
• Subtask 2: 5 / 5
• Subtask 3: 11 / 11
• Subtask 4: 18 / 18
• Subtask 5: 0 / 26
• Subtask 6: 0 / 36