Submission #1235086

#	Time	Username	Problem	Language	Result	Execution time	Memory
1235086		Zbyszek99	Parachute rings (IOI12_rings)	C++20	100 / 100	1160 ms	261352 KiB

rings

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define ull unsigned long long
#define ff first
#define ss second
#define pii pair<int,int>
#define pll pair<long long, long long>
#define vi vector<int>
#define vl vector<long long>
#define pb push_back
#define rep(i, b) for(int i = 0; i < (b); ++i)
#define rep2(i,a,b) for(int i = a; i <= (b); ++i)
#define rep3(i,a,b,c) for(int i = a; i <= (b); i+=c)
#define count_bits(x) __builtin_popcountll((x))
#define all(x) (x).begin(),(x).end()
#define siz(x) (int)(x).size()
#define forall(it,x) for(auto& it:(x))
using namespace __gnu_pbds;
using namespace std;
typedef tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;
//mt19937 mt;void random_start(){mt.seed(chrono::time_point_cast<chrono::milliseconds>(chrono::high_resolution_clock::now()).time_since_epoch().count());}
//ll los(ll a, ll b) {return a + (mt() % (b-a+1));}
const int INF = 1e9+50;
const ll INF_L = 1e18+40;
const ll MOD = 1e9+7;

const int maxn = 1000'001;

int n;
vi graph[maxn];
set<int> out_edges[maxn];
int cnt[maxn];
int my_bad[maxn];
bool is_in[maxn];
bool is_in_c[maxn];
int rep_[maxn];
int cur_not_good;
int four = -1;
bool is_four = 1;
bool is_zero = 0;
bool is_cycle = 0;
set<int> on;

int fint(int v)
{
    if(rep_[v] == v) return v;
    rep_[v] = fint(rep_[v]);
    return rep_[v];
}

void onion(int a, int b)
{
    rep_[fint(a)] = fint(b);
}

void add_one(int v)
{
    if(!is_in[v]) return;
    cnt[my_bad[v]]--;
    my_bad[v]++;
    cnt[my_bad[v]]++;
}

void Init(int N) 
{
    n = N;
    cnt[0] = n;
    rep(i,n) 
    {
        is_in[i] = 1;
        rep_[i] = i;
    }
}

vi cycle;
bool odw[maxn];

bool find_cycle(int v, int dest)
{
    cycle.pb(v);
    if(v == dest) return 1;
    odw[v] = 1;
    forall(it,graph[v])
    {
        if(odw[it] == 0)
        {
            bool w = find_cycle(it,dest);
            if(w) return w;
        }
    }
    cycle.pop_back();
    return 0;
}

vector<pii> opers;

void set_four(int v)
{
    four = v;
    rep(i,n)
    {
        rep_[i] = i;
        graph[i] = {};
    }
    forall(it,opers)
    {
        if(it.ff == v || it.ss == v) continue;
        if(fint(it.ff) == fint(it.ss)) 
        {
            is_four = 0;
        }
        graph[it.ff].pb(it.ss);
        graph[it.ss].pb(it.ff);
        onion(it.ff,it.ss);
        if(siz(graph[it.ff]) > 2 || siz(graph[it.ss]) > 2) 
        {
            is_four = 0;
        }
    }
}

void Link(int A, int B) 
{   
    opers.pb({A,B});
    if(is_zero) return;
    if(four != -1)
    {
        if(A == four || B == four) return;
        if(fint(A) == fint(B)) 
        {
            is_four = 0;
            return;
        }
        graph[A].pb(B);
        graph[B].pb(A);
        onion(A,B);
        if(siz(graph[A]) > 2 || siz(graph[B]) > 2) 
        {
            is_four = 0;
        }
        return;
    }
    if(siz(graph[A]) == 2) 
    {
        add_one(A);
        cur_not_good++;
    }
    if(siz(graph[B]) == 2) 
    {
        add_one(B);
        cur_not_good++;
    }
    if(siz(graph[A]) == 3)
    {
        set_four(A);
        return;
    }
    if(siz(graph[B]) == 3)
    {
        set_four(B);
        return;
    }
    graph[A].pb(B);
    graph[B].pb(A);
    out_edges[A].insert(B);
    out_edges[B].insert(A);
    if(is_cycle)
    {
        if(fint(A) == fint(B))
        {
            int is1 = (is_in_c[A] == 1);
            int is2 = (is_in_c[B] == 1);
            if(is1 + is2 == 0)
            {
                is_zero = 1;
                return;
            }
            if(is1 + is2 == 1)
            {
                if(is_in[A])
                {
                    vi to_del;
                    forall(it,on)
                    {
                        if(it == A) continue;
                        if(out_edges[it].find(B) == out_edges[it].end() || out_edges[it].find(A) == out_edges[it].end())
                        {
                            to_del.pb(it);
                        }
                    }
                    forall(it,to_del)
                    {
                        on.erase(on.find(it));
                        cnt[my_bad[it]]--;
                        is_in[it] = 0;
                    }
                }
                if(is_in[B])
                {
                    vi to_del;
                    forall(it,on)
                    {
                        if(it == B) continue;
                        if(out_edges[it].find(A) == out_edges[it].end() || out_edges[it].find(B) == out_edges[it].end())
                        {
                            to_del.pb(it);
                        }
                    }
                    forall(it,to_del)
                    {
                        on.erase(on.find(it));
                        cnt[my_bad[it]]--;
                        is_in[it] = 0;
                    }
                }
            }
            if(is1 + is2)
            {
                vi to_del;
                forall(it,on)
                {
                    if(it == A || it == B) continue;
                    cnt[my_bad[it]]--;
                    is_in[it] = 0;
                }
                forall(it,to_del) on.erase(on.find(it));
            }
        }
    }
    else
    {
        if(fint(A) == fint(B))
        {
            is_cycle = 1;
            find_cycle(A,B);
            rep(i,n)
            {
                cnt[my_bad[i]]--;
                is_in[i] = 0;
            }
            forall(it,cycle)
            {
                is_in[it] = 1;
                cnt[my_bad[it]]++;
                on.insert(it);
                is_in_c[it] = 1;
            }
        }
    }
    onion(A,B);
    if(siz(graph[A]) > 2)
    {
        forall(it,graph[A])
        {
            add_one(it);
        }
    }
    if(siz(graph[B]) > 2)
    {
        forall(it,graph[B])
        {
            add_one(it);
        }
    }
}

int CountCritical() 
{
   // cerr << is_zero << " " << four << " " << cnt[cur_not_good] << " " << is_cycle << " ans\n";
    if(is_zero) return 0;
    if(four != -1)
    {
        if(is_four) return 1;
        return 0;
    }
    return cnt[cur_not_good];
}

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