Submission #1105417

#	Time	Username	Problem	Language	Result	Execution time	Memory
1105417		minhvule	Hotspot (NOI17_hotspot)	C++17	100 / 100	1078 ms	1524 KiB

hotspot

#include <bits/stdc++.h>
#define int long long
#define pb push_back
#define freo(task) if(fopen(task".inp", "r")){ freopen(task".inp", "r", stdin); freopen(task".out", "w", stdout); }
#define FOR(i, a, b) for(int i=(a),_b = (b); i<=_b; i++)
#define FORD(i, a, b) for(int i=(a),_b = (b); i>=_b; i--)
#define pii pair<int, int>
using namespace std;

const int N = 5e3 + 5;
int n, m, k, pa[N], pb[N], da[N], db[N];
vector<int> g[N];
double sum[N];

void dijkstra(int u, int d[], int pa[]) {
    priority_queue<pii, vector<pii>, greater<pii>> pq; // Use a min-heap for Dijkstra
    d[u] = 0;
    pq.push({0, u});
    while (!pq.empty()) {
        pii top = pq.top();
        pq.pop();
        int u = top.second;
        if (top.first > d[u]) continue;
        for (int v : g[u]) {
            if (d[v] > d[u] + 1) {
                d[v] = d[u] + 1;
                pa[v] = pa[u]; // Carry the path count from u
                pq.push({d[v], v});
            } else if (d[v] == d[u] + 1) {
                pa[v] += pa[u]; // Accumulate path counts
            }
        }
    }
}

void sub6() {
    FOR(i, 1, m) {
        int u, v; 
        cin >> u >> v;
        g[u].pb(v);
        g[v].pb(u);
    }
    cin >> k;
    FOR(i, 1, k) {
        int a, b; 
        cin >> a >> b;
        
        FOR(i, 0, n) 
            da[i] = db[i] = INT_MAX, pa[i] = pb[i] = 1; // Initialize distance and path counts

        dijkstra(a, da, pa);
        dijkstra(b, db, pb);

        FOR(u, 0, n) 
            if (da[u] + db[u] == da[b]) {
                sum[u] += (pa[u] * pb[u] * 1.0) / pa[b];
            }
    }
    
    int ans = 0;
    FOR(i, 0, n) 
        if (sum[i] > sum[ans]) 
            ans = i;

    cout << ans;
}

void solve() {
    cin >> n >> m;
    sub6();
}

int32_t main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr); 
    cout.tie(nullptr);
    freo("TRAINCENTRE");
    solve();
    return 0;
}

Compilation message (stderr)

hotspot.cpp: In function 'int32_t main()':
hotspot.cpp:4:55: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    4 | #define freo(task) if(fopen(task".inp", "r")){ freopen(task".inp", "r", stdin); freopen(task".out", "w", stdout); }
      |                                                ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
hotspot.cpp:77:5: note: in expansion of macro 'freo'
   77 |     freo("TRAINCENTRE");
      |     ^~~~
hotspot.cpp:4:88: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    4 | #define freo(task) if(fopen(task".inp", "r")){ freopen(task".inp", "r", stdin); freopen(task".out", "w", stdout); }
      |                                                                                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
hotspot.cpp:77:5: note: in expansion of macro 'freo'
   77 |     freo("TRAINCENTRE");
      |     ^~~~

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