Submission #1165063

#	Time	Username	Problem	Language	Result	Execution time	Memory
1165063		DangKhoizzzz	Hotspot (NOI17_hotspot)	C++20	0 / 100	10 ms	17220 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;

    queue <int> Q;
    Q.push(st);
    while(!Q.empty())
    {
        int u = Q.front();
        Q.pop();
        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];
                Q.push(v);
            }
            else if(f[st][v] == f[st][u] + 1)
            {
                ways[st][v] += ways[st][u];
            }
        }
    }
}

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;
    }

    for(int u = 1; u <= n; u++)
    {

        int total = 0 , sum = 0;
        bool check = 1;

        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])
            {
                check = 0; break;
            }
            sum += ways[query[i].fi][u] * ways[query[i].se][u];
            total += ways[query[i].fi][query[i].se];
        }
        if(check)
        {
            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);
    solve();
    return 0;
}

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