Submission #1114514

#	Time	Username	Problem	Language	Result	Execution time	Memory
1114514		asli_bg	Duathlon (APIO18_duathlon)	C++11	0 / 100	56 ms	33352 KiB

count_triplets

#include <bits/stdc++.h>
using namespace std;

#define int long long

#define fi first
#define se second
#define all(x) x.begin(),x.end()
#define sp <<' '<<
#define pb push_back

#define FOR(i,a) for(int i=0;i<(a);i++)
#define FORE(i,a,b) for(int i=(a);i<(b);i++)

#define cont(a) for(auto el:a) cout<<el<<' '; cout<<endl;
#define contp(a) for(auto el:a) cout<<el.fi<<'-'<<el.se<<' ';cout<<endl;

#define DEBUG(x) cout<<#x sp ":" sp x<<endl;

typedef vector<int> vi;
typedef pair<int,int> pii;
typedef vector<pii> vii;
typedef long long ll;

#define endl '\n'
#define mid (l+r)/2

const int MAXN=2e5+5;

int n,m;
vi adj[MAXN];

int low[MAXN], dep[MAXN], sub[MAXN], leaf[MAXN];
bool vis[MAXN];

int ans;

int back;

int tut[MAXN];

void dfs(int nd,int ata,int h){
    dep[nd]=h;
    sub[nd]=0;
    low[nd]=h;

    multiset<int> s;

    for(auto kom:adj[nd]){
        if(kom==ata) continue;
        if(vis[kom]){
            if(dep[kom]<dep[nd]){ //benden giden back edge
                if(low[nd]>=dep[kom]) tut[nd]=nd;
                low[nd]=min(low[nd],dep[kom]);
            }
            continue;
        }

        vis[kom]=true;
        dfs(kom,nd,h+1);

        sub[nd]+=sub[kom];
        s.insert(sub[kom]);

        if(low[nd]>=low[kom]) tut[nd]=tut[kom];
        low[nd]=min(low[nd],low[kom]);
    }

    int kalan=n-sub[nd]-1;

    int ekle=0;
    
    ekle+=sub[nd]*(kalan);  //yukarıyla aşağı arası

    if(low[nd]<=h){ //back edge varsa
        int bir=max(0LL,(dep[nd]-low[nd]-1)); //cycleda olan yukarı kısım
        int iki=kalan-bir; //cycleda olmayan yukarı kısım

        ekle+=bir*iki;

        bir=max(0LL,dep[tut[nd]]-dep[nd]-1); //cycleda olan aşağı kısım
        iki=sub[tut[nd]]; //cycyleda olmayan aşağı kısım

        ekle+=bir*iki;
    }

    /*cout<<endl;
    DEBUG(nd);
    DEBUG(sub[nd]);
    cont(s);

    DEBUG(tut[nd]);
    DEBUG(sub[tut[nd]]);*/

    ekle*=2;

    for(auto el:s) ekle+=(sub[nd]-el)*el; //subtreeler arası

    ans+=ekle;

    //DEBUG(ekle);
    //DEBUG(ans);

    sub[nd]++;
}

signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    cin>>n>>m;
    FOR(i,m){
        int a,b;
        cin>>a>>b;
        adj[a].pb(b);
        adj[b].pb(a);
    }

    ans=0;
    back=0;
    vis[1]=true;
    dfs(1,-1,0);

    cout<<ans<<endl;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 8
• Subtask 4: 0 / 10
• Subtask 5: 0 / 13
• Subtask 6: 0 / 15
• Subtask 7: 0 / 20
• Subtask 8: 0 / 8
• Subtask 9: 0 / 10