Submission #1190275

#	Time	Username	Problem	Language	Result	Execution time	Memory
1190275		Malix	철인 이종 경기 (APIO18_duathlon)	C++20	100 / 100	96 ms	29256 KiB

count_triplets

#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef pair<int,int> pi;
typedef vector<pi> pii;
typedef tuple<ll,ll,ll> ti;
typedef vector<ll> li;
typedef vector<li> lii;
 
#define REP(i,a,b) for(int i=a;i<b;i++)
#define F first
#define S second
#define PB push_back
#define LSOne(s) ((s)&(-s))
 
ll INF=1000000000000000010;
int inf=1e9+10;
ll M=1e9+7;

int n,m,k,c=0;
vii a,b;
vi low,num;
stack<int> st;
ll ans=0;
vector<ll> sz;

void dfs(int x,int y){
    st.push(x);
    low[x]=k;num[x]=k;
    k++;
    for(auto u:a[x])if(u!=y){
        if(num[u]!=-1){
            low[x]=min(low[x],num[u]);
            continue;
        }
        dfs(u,x);
        low[x]=min(low[x],low[u]);
        if(low[u]>=num[x]){
            b[x].PB(n+c);
            while(b[n+c].empty()||b[n+c].back()!=u){
                b[n+c].PB(st.top());
                st.pop();
            }
            c++;
        }
    }
}

void dfs2(int x){
    if(x<n)sz[x]++;
    for(auto u:b[x]){
        dfs2(u);
        sz[x]+=sz[u];
        if(x>=n)ans-=b[x].size()*sz[u]*(sz[u]-1);
    }
    ll t=(ll)k-sz[x];
    if(x>=n)ans-=b[x].size()*t*(t-1);
}

int main() {   
// ios::sync_with_stdio(0);
// cin.tie(0);
    cin>>n>>m;
    a.resize(n);b.resize(2*n);sz.resize(2*n,0);
    REP(i,0,m){
        int x,y;cin>>x>>y;
        x--;y--;
        a[x].PB(y);
        a[y].PB(x);
    }
    low.resize(n,-1);num.resize(n,-1);
    REP(i,0,n)if(num[i]==-1){
        st=stack<int>();
        k=0;
        dfs(i,-1);
        ans+=(ll)k*(k-1)*(k-2);
        dfs2(i);
    }
    cout<<ans;
}

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