제출 #553451

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
553451		urosk	철인 이종 경기 (APIO18_duathlon)	C++14	0 / 100	206 ms	35272 KiB

count_triplets

// __builtin_popcount(x)
// __builtin_popcountll(x)
#define here cerr<<"===========================================\n"
#include <bits/stdc++.h>
#define ld double
#define ll long long
#define ull unsigned long long
#define llinf 100000000000000000LL // 10^17
#define iinf 2000000000 // 2*10^9
#define pb push_back
#define popb pop_back
#define fi first
#define sc second
#define endl '\n'
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pld pair<ld,ld>
#define sz(a) int(a.size())
#define all(a) a.begin(),a.end()
#define ceri(a,l,r) {for(ll i_ = l;i_<=r;i_++) cerr<<a[i_]<< " ";cerr<<endl;}
using namespace std;

#define maxn 100005
ll n,m;
vector<ll> g[maxn];
vector<ll> v[maxn];
ll low[maxn];
ll in[maxn];
bool vis[maxn];
ll it = 1;
vector<pll> br;
map<pll,bool> mp;
ll dsu[maxn];
ll siz[maxn];
ll sub[maxn];
ll root(ll x){
    while(x!=dsu[x]){
        dsu[x] = dsu[dsu[x]];
        x = dsu[x];
    }
    return x;
}
void upd(ll x,ll y){
    x = root(x);
    y = root(y);
    dsu[x] = y;
    siz[y] += siz[x];
}
void dfs(ll u,ll par){
    in[u] = it++;
    low[u] = in[u];
    for(ll s : g[u]){
        if(s==par) continue;
        if(in[s]==0){
            dfs(s,u);
            low[u] = min(low[u],low[s]);
        }else low[u] = min(low[u],in[s]);
    }
    if(u!=par&&low[u]>in[par]){
        br.pb({u,par});
        mp[{u,par}] = 1;
        mp[{par,u}] = 1;
    }
}
void dfs2(ll u){
    vis[u] = 1;
    for(ll s : g[u]){
        if(mp[{u,s}]) continue;
        if(vis[s]) continue;
        upd(u,s);
        dfs2(s);
    }
}
ll ans = 0;
ll f3(ll x){
    return x*(x-1)*(x-2)/6;
}
ll f2(ll x){
    return x*(x-1)/2;
}
ll pari[maxn];
ll sizi = 0;
void dfs3(ll u,ll par){
    pari[u] = par;
    vis[u] = 1;
    ans+=f3(siz[u])*6;
    sub[u] = 0;
    for(ll s : v[u]){
        if(s==par) continue;
        dfs3(s,u);
        sub[u]+=sub[s]+siz[s];
    }
    //cerr<<u<< " "<<sub[u]<<" "<<siz[u]<<endl;
    ans+=(sub[u]*siz[u]*(sizi-siz[u]-sub[u])+f2(siz[u])*sub[u]*2 + f2(siz[u])*(sizi-sub[u]-siz[u])*2)*2;
    ans-=(siz[u]-1)*sub[u]*2;
    ans-=(siz[u]-1)*(sizi-siz[u]-sub[u])*2;
}
ll dfs4(ll u,ll par){
    ll sum = siz[u];
    for(ll s : v[u]){
        if(s==par) continue;
        sum+=dfs4(s,u);
    }
    return sum;
}
int main(){
	ios_base::sync_with_stdio(false);cerr.tie(0);cout.tie(0);cin.tie(0);
    cin >> n >> m;
    for(ll i = 1;i<=m;i++){
        ll x,y; cin >> x >> y;
        g[x].pb(y);
        g[y].pb(x);
    }
    iota(dsu+1,dsu+n+1,1);
    fill(siz+1,siz+n+1,1);
    for(ll i = 1;i<=n;i++) if(in[i]==0) dfs(i,i);
    //here;
    for(ll i = 1;i<=n;i++){
        if(vis[i]) continue;
        dfs2(i);
    }
    for(pll p : br){
        ll x = root(p.fi);
        ll y = root(p.sc);
        v[x].pb(y);
        v[y].pb(x);
    }
    fill(vis,vis+n+1,0);
    //here;
    //for(ll i = 1;i<=n;i++) cerr<<i<< " "<<root(i)<< " "<<siz[root(i)]<<endl;
    //here;
    //for(ll i = 1;i<=n;i++){
        //cerr<<"i: "<<i<<endl;
        //for(ll x : v[i]) cerr<<x<< " ";
        //cerr<<endl;
    //}
    //here;
    for(ll i = 1;i<=n;i++){
        ll j = root(i);
        if(vis[j]==0){
            sizi = dfs4(j,j);
            //cerr<<"j: "<<j<< " "<<sizi<<endl;
            dfs3(j,j);
            //cerr<<endl;
        }
    }
    cout<<ans<<endl;
	return 0;
}
/*
4 3
1 2
2 3
3 4
out: 8
*/
/*
4 4
1 2
2 3
3 4
4 2
out: 14
*/

• 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