Submission #1105402

#	Time	Username	Problem	Language	Result	Execution time	Memory
1105402		minhvule	Hotspot (NOI17_hotspot)	C++17	0 / 100	1 ms	592 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 bit(x, i) ((x >> i) & 1)
#define oo 1e18
#define pii pair<int, int>
#define debug cout<<"VUDEPTRAI\n";
using namespace std;
// mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
// ll rand(ll l, ll r) { assert(l <= r); return uniform_int_distribution<ll>(l, r)(rd); }
const int N = 5e3 + 5;
int n, m, k;
vector<int> g[N], s;
void dijkstra(int u, vector<int> &d){
    priority_queue<pii> pq;
    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;
                pq.push({d[v], v});
            }
    }
}
void calc(vector<int> d, vector<int> &pa){
    for(int u:s)
        for(int v:g[u])
            if(d[u] == d[v] + 1)
                pa[u] += pa[v];
}
void sub6(){
    FOR(i, 1, m){
        int u, v; cin>>u>>v;
        g[u].pb(v);
        g[v].pb(u);
    }
    cin>>k;
    int ans = -1, tmp = INT_MIN;
    FOR(i, 1, k){
        int a, b; cin>>a>>b;
        s.clear();
        vector<int> da(N, INT_MAX);
        vector<int> db(N, INT_MAX);
        vector<int> pa(N, 0);
        vector<int> pb(N, 0);
        dijkstra(a, da);
        dijkstra(b, db);
        FOR(u, 0, n)
            if(da[u] + db[u] == da[b]) s.pb(u);
        pa[a] = 1;
        pb[b] = 1;
        calc(da, pa);
        calc(db, pb);
        for(int u:s) if(pa[b] != 0){
            int sum = pa[u] * pb[u] / pa[b];
            if(sum > tmp){
                tmp = sum;
                ans = u;
            }
        }
        // for(int u:s[i]) cout<<u<<" ";
        // cout<<'\n';
    }
    cout<<ans;
}
void solve(){
    cin>>n>>m;
    sub6();
}
int32_t main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
    // freo("");
    solve();
    // cerr << "\nTime: " << 1.0 * clock() / CLOCKS_PER_SEC << "s\n";
    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