Submission #673301

#	Time	Username	Problem	Language	Result	Execution time	Memory
673301		Alihan_8	Shymbulak (IZhO14_shymbulak)	C++17	50 / 100	1567 ms	9392 KiB

shymbulak

#include <bits/stdc++.h>
// include <ext/pb_ds/assoc_container.hpp>
// include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;
using namespace std;
#define all(x) x.begin(), x.end()
#define pb push_back
// define ordered_set tree<int,null_type,less_equal<int>,rb_tree_tag,tree_order_statistics_node_update>
#define mpr make_pair
#define ln '\n'
void IO(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
#define int long long
signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int n; cin >> n;
    vector <int> g[n];
    for ( int i = 1; i <= n; i++ ){
        int x, y; cin >> x >> y;
        g[--x].pb(--y);
        g[y].pb(x);
    }
    map <int,int> mp;
    auto djkstra = [&](int x){
        vector <int> dis(n, -1), dp(n);
        dis[x] = 0; dp[x] = 1;
        queue <int> q; q.push(x);
        while ( !q.empty() ){
            int cur = q.front(); q.pop();
            for ( auto to: g[cur] ){
                if ( dis[to] != -1 ){
                    if ( dis[to] == dis[cur]+1 ) dp[to] += dp[cur];
                }
                else{
                    dis[to] = dis[cur]+1;
                    dp[to] = dp[cur];
                    q.push(to);
                }
            }
        }
        for ( int i = 0; i < n; i++ ) mp[dis[i]] += dp[i];
    };
    for ( int i = 0; i < n; i++ ){
        djkstra(i);
    }
    int cnt = mp.rbegin()->second;
    cout << cnt/2;

    cout << '\n';
}

Compilation message (stderr)

shymbulak.cpp: In function 'void IO(std::string)':
shymbulak.cpp:11:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 | void IO(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
shymbulak.cpp:11:70: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 | void IO(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
      |                                                               ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 20 / 20
• Subtask 3: 0 / 50