제출 #658892

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
658892		JooDdae	산만한 고양이 (KOI17_cat)	C++17	23 / 100	408 ms	88848 KiB

cat

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

int n, m;

int in[300200], low[300200], cnt;
vector<int> v[300200];
stack<pair<int, int>> st;
vector<vector<pair<int, int>>> bcc;
set<int> ns;

int dfs(int u, int p){
    in[u] = low[u] = ++cnt;

    for(auto x : v[u]) if(x != p){
        if(in[u] > in[x]) st.push({u, x});

        if(in[x]) low[u] = min(low[u], in[x]);
        else{
            low[u] = min(low[u], dfs(x, u));
            if(low[x] >= in[u]){
                vector<pair<int, int>> b;
                while(st.top() != make_pair(u, x)) b.push_back(st.top()), st.pop();
                b.push_back(st.top()), st.pop();
                if(b.size() > 1) bcc.push_back(b);
                else ns.insert(b[0].first), ns.insert(b[0].second);
            }
        }
    }

    return low[u];
}


int main(){
    cin.tie(0)->sync_with_stdio(0);
    cin >> n >> m;
    for(int i=1;i<=m;i++) {
        int a, b; cin >> a >> b;
        v[a].push_back(b), v[b].push_back(a);
    }

    dfs(1, 0);
    if(bcc.size() > 1) return cout << "0\n", 0;

    set<int> s;
    for(auto b : bcc) for(auto [x, y] : b) s.insert(x), s.insert(y);

    ll ans = 0;
    for(int i=1;i<=n;i++) if(m-(int)v[i].size() == n-2 && (bcc.empty() || (s.count(i) && !ns.count(i)))) ans += i;
    cout << ans;
}

• Subtask 1: 0 / 12
• Subtask 2: 0 / 10
• Subtask 3: 23 / 23
• Subtask 4: 0 / 55