Submission #1105404

#	Time	Username	Problem	Language	Result	Execution time	Memory
1105404		vukhacminh	Hotspot (NOI17_hotspot)	C++17	100 / 100	605 ms	36176 KiB

hotspot

/**
*    Author :  Vu Khac Minh
*    Created : 08.03.2024
**/
#include <bits/stdc++.h>
#define MASK(x) ((1ll) << (x))
#define BIT(x, i) (((x) >> (i)) & (1))
#define c_bit(i) __builtin_popcountll(i) 
#define SET_ON(x, i) ((x) | MASK(i)) 
#define SET_OFF(x, i) ((x) & ~MASK(i)) 
#define ALL(v) (v).begin(), (v).end()
#define REP(i, n) for (int i = 0, _n = (n); i < _n; ++i)
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define FORD(i, b, a) for (int i = (b), _a = (a); i >= _a; --i)
#define db(val) "["#val" = " << (val) << "] "
#define ll long long
using namespace std;
const int maxn = 1e6 + 5;
const int mod = 1e9+7;

void file()
{
    #define Task "ROUNDPRI"
    if(fopen(Task".inp","r"))
    {
        freopen(Task".inp","r",stdin);
        freopen(Task".out","w",stdout);
    }
}

int n, m, k;
vector<int> adj[maxn];
ll dista[maxn], distb[maxn], cnta[maxn], cntb[maxn];
long double res[maxn];

void bfs(int s, ll dist[], ll cnt[])
{
    FOR(u, 0, n - 1)
    {
        dist[u] = 1e18;
        cnt[u] = 0;
    }
    dist[s] = 0;
    cnt[s] = 1;
    queue<int> q;
    q.push(s);
    while (!q.empty()) {
        int u = q.front(); q.pop();
        for (int v : adj[u]) {
            if (dist[u] + 1 < dist[v]) {
                dist[v] = dist[u] + 1;
                cnt[v] = cnt[u];
                q.push(v);
            } else if (dist[u] + 1 == dist[v]) {
                cnt[v] += cnt[u];
            }
        }
    }
}

void solve()
{
    cin >> n >> m;
    FOR(i, 1, m)
    {
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    cin >> k;
    FOR(i, 1, k)
    {
        int a, b;
        cin >> a >> b;
        bfs(a, dista, cnta);
        bfs(b, distb, cntb);
        FOR(u, 0, n - 1)
        {
            if (dista[u] + distb[u] == dista[b])
            {
                long double c = cnta[u] * cntb[u];
                res[u] += c / cnta[b];
            }
        }
    }
    long double best = 0;
    int pos = 0;
    FOR(i, 0, n - 1)
    {
        if (res[i] > best)
        {
            best = res[i];
            pos = i;
        }
    }
    cout << pos << endl;
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int ntest = 1;
    file();
    //cin >> ntest;
    while (ntest--)
    {
        solve();
    }

    return 0;
}

Compilation message (stderr)

hotspot.cpp: In function 'void file()':
hotspot.cpp:26:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   26 |         freopen(Task".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
hotspot.cpp:27:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |         freopen(Task".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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