Submission #250461

#	Time	Username	Problem	Language	Result	Execution time	Memory
250461		rrrr10000	Duathlon (APIO18_duathlon)	C++14	31 / 100	237 ms	34924 KiB

count_triplets

#include <bits/stdc++.h>
using namespace std;
#define rep(i, n)  for(long long i=0;i<(long long)(n);i++)
#define REP(i,k,n) for(long long i=k;i<(long long)(n);i++)
#define all(a) a.begin(),a.end()
#define pb emplace_back
#define eb emplace_back
#define lb(v,k) (lower_bound(all(v),k)-v.begin())
#define ub(v,k) (upper_bound(all(v),k)-v.begin())
#define fi first
#define se second
#define pi M_PI
#define PQ(T) priority_queue<T>
#define SPQ(T) priority_queue<T,vector<T>,greater<T>>
#define dame(a) {out(a);return 0;}
#define decimal cout<<fixed<<setprecision(15);
#define dupli(a) a.erase(unique(all(a)),a.end())
typedef long long ll;
typedef pair<ll,ll> P;
typedef tuple<ll,ll,ll> PP;
typedef tuple<ll,ll,ll,ll> PPP;
typedef multiset<ll> S;
using vi=vector<ll>;
using vvi=vector<vi>;
using vvvi=vector<vvi>;
using vvvvi=vector<vvvi>;
using vp=vector<P>;
using vvp=vector<vp>;
using vb=vector<bool>;
using vvb=vector<vb>;
const ll inf=1001001001001001001;
const ll INF=1001001001;
const ll mod=1000000007;
const double eps=1e-10;
template<class T> bool chmin(T&a,T b){if(a>b){a=b;return true;}return false;}
template<class T> bool chmax(T&a,T b){if(a<b){a=b;return true;}return false;}
template<class T> void out(T a){cout<<a<<'\n';}
template<class T> void outp(T a){cout<<'('<<a.fi<<','<<a.se<<')'<<'\n';}
template<class T> void outvp(T v){rep(i,v.size())cout<<'('<<v[i].fi<<','<<v[i].se<<')';cout<<'\n';}
template<class T> void outvvp(T v){rep(i,v.size())outvp(v[i]);}
template<class T> void outv(T v){rep(i,v.size()){if(i)cout<<' ';cout<<v[i];}cout<<'\n';}
template<class T> void outvv(T v){rep(i,v.size())outv(v[i]);}
template<class T> bool isin(T x,T l,T r){return (l)<=(x)&&(x)<=(r);}
template<class T> void yesno(T b){if(b)out("yes");else out("no");}
template<class T> void YesNo(T b){if(b)out("Yes");else out("No");}
template<class T> void YESNO(T b){if(b)out("YES");else out("NO");}
template<class T> void noyes(T b){if(b)out("no");else out("yes");}
template<class T> void NoYes(T b){if(b)out("No");else out("Yes");}
template<class T> void NOYES(T b){if(b)out("NO");else out("YES");}
void outs(ll a,ll b){if(a>=inf-100)out(b);else out(a);}
ll gcd(ll a,ll b){if(b==0)return a;return gcd(b,a%b);}
ll modpow(ll a,ll b){ll res=1;a%=mod;while(b){if(b&1)res=res*a%mod;a=a*a%mod;b>>=1;}return res;}

vvp g;
vb used;
vi group;
ll ans=0;
void scan(int i){
    used[i]=true;
    group.pb(i);
    for(auto x:g[i])if(!used[x.fi])scan(x.fi);
}
ll c,ce;
vi gv,ge,lk,ord;
vb back_edge;
void dfs(int i,int p,int e){
    for(auto x:g[i])if(x.fi!=p){
        if(ord[x.fi]==-1){
            ord[x.fi]=c++;
            dfs(x.fi,i,x.se);
            chmin(lk[i],lk[x.fi]);
        }
        else{
            chmin(lk[i],ord[x.fi]);
            back_edge[x.se]=true;
        }
    }
}
void dfs1(int i,int p,int e){
    vp dl;
    for(auto x:g[i]){
        if(!back_edge[x.se]&&x.fi!=p){
            if(p!=-1){
                if(lk[x.fi]>=ord[i]){
                    gv[i]=-1;
                    ge[x.se]=ce++;
                    // cout<<i<<' '<<x.se<<' '<<ge[x.se]<<endl;
                }
                else ge[x.se]=ge[e];
                dfs1(x.fi,i,x.se);
            }
            else dl.pb(x);
        }
        else if(x.fi!=p&&ord[x.fi]<ord[i])ge[x.se]=ge[e];
    }
    if(p==-1){
        for(auto x:dl){
            ge[x.se]=ce++;
            dfs1(x.fi,i,x.se);
        }
        if(dl.size()==1)gv[i]=0;
        else gv[i]=-1;
    }
    else if(gv[i]==-2)gv[i]=ge[e];
}
vi f,sz,par;
vvi edge;
ll getsz(int i,int p){
    par[i]=p;
    if(i>=ce)sz[i]=1;
    else sz[i]=f[i];
    for(ll x:edge[i])if(x!=p){
        sz[i]+=getsz(x,i);
    }
    return sz[i];
}
int main(){
    ll n,m;cin>>n>>m;
    g=vvp(n);
    used=vb(n,false);
    rep(i,m){
        ll a,b;cin>>a>>b;a--;b--;
        g[a].pb(b,i);g[b].pb(a,i);
    }
    lk=vi(n,inf);
    gv=vi(n,-2);
    ge=vi(m);
    back_edge=vb(m,false);
    ord=vi(n,-1);
    rep(i,n){
        if(used[i])continue;
        group=vi(0);
        scan(i);
        if(group.size()<3)continue;
        ord[i]=0;
        c=1;
        ce=0;
        dfs(i,-1,-1);
        // outv(lk);outv(ord);
        dfs1(i,-1,-1);
        ll cnt=0;
        // outv(gv);outv(ge);
        f=vi(ce);
        for(ll x:group){
            if(gv[x]==-1)gv[x]=ce+(cnt++);
            else f[gv[x]]++;
        }
        edge=vvi(cnt+ce);
        for(ll x:group){
            if(gv[x]>=ce)for(auto to:g[x]){
                edge[gv[x]].pb(ge[to.se]);
                edge[ge[to.se]].pb(gv[x]);
            }
        }
        rep(j,cnt+ce)dupli(edge[j]);
        // // out(ce);out(cnt);
        // out("edge");
        // outvv(edge);
        // outv(f);
        par=vi(ce+cnt);sz=vi(ce+cnt);
        getsz(0,-1);
        vi s(ce);
        rep(i,ce){
            for(ll x:edge[i])if(x!=par[i])s[i]+=sz[x]*(sz[x]-1);
            ans+=f[i]*((group.size()-1)*(group.size()-2)-s[i]);
            if(par[i]!=-1)ans-=f[i]*(group.size()-sz[i])*(group.size()-sz[i]-1);
            // outp(P(i,ans));
        }
        // outv(s);
        REP(i,ce,ce+cnt){
            ans+=(group.size()-1)*(group.size()-2);
            for(ll x:edge[i])if(x!=par[i])ans-=s[x];
            // out(ans);
            ll p=par[i];
            ans-=(s[p]+(group.size()-sz[p])*(group.size()-sz[p]-1)-sz[i]*(sz[i]-1));
            // outp(P(i,ans));
        }
    }
    out(ans);
}

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