Submission #548979

#	Time	Username	Problem	Language	Result	Execution time	Memory
548979		leaked	Duathlon (APIO18_duathlon)	C++17	49 / 100	116 ms	54484 KiB

count_triplets

#include <bits/stdc++.h>

#define f first
#define s second
#define m_p make_pair
#define vec vector
#define pb push_back
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define sz(x) (int)(x).size()
#define pw(x) (1LL<<(x))
#define fast_prep ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;
typedef pair<int,int> pii;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pll;
typedef unsigned long long ull;
//#define int long long
template<class T> bool umin(T &a,const T &b){return (a>b?a=b,1:0);}
template<class T> bool umax(T &a,const T &b){return (a<b?a=b,1:0);}
const int N=1e5+1;
vec<int> g[N];
vec<int> gr[2*N];
int sz[2*N];
int n;
vec<pii> vc;
int in[N],fup[N],tt=1;
vec<vec<pii>> wo;
int cm=1;
int siz[N];
void dfs1(int v,int p){
    in[v]=fup[v]=tt++;
    for(auto &z : g[v]){
        if(z==p) continue;
//        cout<<
        if(in[z]){
            umin(fup[v],in[z]);
            if(in[z]<in[v]) vc.pb({v,z});
        }
        else{
            vc.pb({v,z});
            dfs1(z,v);
            umin(fup[v],fup[z]);
            if(fup[z]>=in[v]){
                vec<pii> cur;
                while(vc.back()!=m_p(v,z)) cur.pb(vc.back()),vc.pop_back();
                cur.pb(vc.back());vc.pop_back();
                wo.pb(cur);
//                cout<<sz(cur)<<endl;
            }
        }
    }
}
int dp[N];
void dfs2(int v,int p){
    dp[v]=(v<=n);
//    cout<<"WE "<<v<<' '<<dp[v]<<endl;
    for(auto &z : gr[v]){
        if(z==p) continue;
        dfs2(z,v);
        dp[v]+=dp[z];
    }
}
ll ans=0;
void dfs3(int v,int full,int p){
    if(v<=n){
        for(auto &z : gr[v]){
            if(z!=p){
                ans-=1ll*(siz[z]-1)*(full-dp[z])*(full-dp[z]-1);
            }
            else{
                ans-=1ll*(siz[z]-1)*(dp[v])*(dp[v]-1);
            }
        }
    }
    for(auto &z : gr[v]) {
        if(z==p) continue;
        dfs3(z,full,v);
    }
}
void init(){
    for(int i=1;i<=n;i++){
        if(!in[i]){

            dfs1(i,i);
            if(sz(vc)) wo.pb(vc);
            vc.clear();
            if(!sz(wo)) continue;

            for(auto &i : wo){
                set<int>st;
                for(auto &j : i) st.insert(j.f),st.insert(j.s);
                siz[n+cm]=sz(st);
                for(auto &j : st) gr[n+cm].pb(j),gr[j].pb(n+cm);
                ++cm;
            }
            wo.clear();
//            if(!sz(wo)) continue;
//            cout<<"WO "<<endl;
            dfs2(n+cm-1,n+cm-1);
            dfs3(n+cm-1,dp[n+cm-1],-1);
            ans+=1ll*dp[n+cm-1]*(dp[n+cm-1]-1)*(dp[n+cm-1]-2);
        }
    }
}
signed main(){
    fast_prep;
    int m;
    cin>>n>>m;
    for(int i=0;i<m;i++){
        int v,u;
        cin>>v>>u;
        g[v].pb(u);g[u].pb(v);
    }
    init();
    cout<<ans;
    return 0;
}
/*
abbaaa
cbbbbccbbccbbbbbbc
(((((((()))())))))
5 5
4 2
2 5
4 1
2 1
4 5

*/

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