Submission #425225

#	Time	Username	Problem	Language	Result	Execution time	Memory
425225		wiwiho	Parachute rings (IOI12_rings)	C++14	55 / 100	4019 ms	108916 KiB

rings

#include <bits/stdc++.h>

#define eb emplace_back
#define printv(a, b) {\
    for(auto pv : a) b << pv << " ";\
    b << "\n";\
}

using namespace std;

int n;

vector<vector<int>> g;
vector<int> in, low;
vector<int> pr;

void Init(int N){
    n = N;
    g.resize(n);
}

void Link(int u, int v){
    g[u].eb(v);
    g[v].eb(u);
}

int ts = 0;

void dfs(int now, int p){
    in[now] = ts++;
    low[now] = in[now];
    pr[now] = p;
    for(int i : g[now]){
        if(in[i] != -1){
            low[now] = min(low[now], in[i]);
            continue;
        }
        dfs(i, now);
        low[now] = min(low[now], low[i]);
    }
}

int CountCritical(){
    ts = 0;
    in.clear();
    low.clear();
    pr.clear();
    in.resize(n, -1);
    low.resize(n);
    pr.resize(n);

    int con = 0;
    for(int i = 0; i < n; i++){
        if(in[i] != -1) continue;
        con++;
        dfs(i, i);
    }

    int zero = 0, one = 0, two = 0, more = 0;
    for(int i = 0; i < n; i++){
        int deg = g[i].size();
        if(deg == 0) zero++;
        else if(deg == 1) one++;
        else if(deg == 2) two++;
        else more++;
    }
  
    int ans = 0;   
    /*cerr << "query " << one << " " << two << " " << more << " " << con << "\n";
    printv(in, cerr);
    printv(low, cerr);
    printv(pr, cerr);*/

    for(int i = 0; i < n; i++){
        int deg = g[i].size();
        if(deg == 0) zero--;
        else if(deg == 1) one--;
        else if(deg == 2) two--;
        else more--;
        for(int j : g[i]){
            int d = g[j].size();
            if(d == 0) zero--;
            else if(d == 1) one--;
            else if(d == 2) two--;
            else more--;
            if(d - 1 == 0) zero++;
            else if(d - 1 == 1) one++;
            else if(d - 1 == 2) two++;
            else more++;
            if(pr[j] == i && low[j] >= in[i]) con++;
        }
        if(pr[i] == i) con--;
        
        //cerr << "test " << i << "\n";
        //cerr << one << " " << two << " " << more << " " << con << "\n";
        if(more == 0 && one == (con - zero) * 2) ans++;

        if(deg == 0) zero++;
        else if(deg == 1) one++;
        else if(deg == 2) two++;
        else more++;
        for(int j : g[i]){
            int d = g[j].size();
            if(d == 0) zero++;
            else if(d == 1) one++;
            else if(d == 2) two++;
            else more++;
            if(d - 1 == 0) zero--;
            else if(d - 1 == 1) one--;
            else if(d - 1 == 2) two--;
            else more--;
            if(pr[j] == i && low[j] >= in[i]) con--;
        }
        if(pr[i] == i) con++;
    }

    return ans;
}

• Subtask 1: 20 / 20
• Subtask 2: 17 / 17
• Subtask 3: 18 / 18
• Subtask 4: 0 / 14
• Subtask 5: 0 / 31