Submission #1059928

#	Time	Username	Problem	Language	Result	Execution time	Memory
1059928		Zbyszek99	Triangles (CEOI18_tri)	C++17	0 / 100	1 ms	604 KiB

tri

#include <bits/stdc++.h>
#include "trilib.h"
#define ll long long
#define ld long double
#define ff first
#define ss second
#define pii pair<int,int>
#define pll pair<long long, 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 size(x) (int)(x).size()
#define forall(it,x) for(auto& it:(x))
using namespace std;
//mt19937 mt;void random(){mt.seed(chrono::time_point_cast<chrono::milliseconds>(chrono::high_resolution_clock::now()).time_since_epoch().count());}
//ll rand(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;

bool odw[501];

void solve()
{
    int n = get_n();
    set<int> s;
    rep2(i,1,n) s.insert(i);
    vector<pii> edges;
    while(size(s) > 1)
    {
        int s1 = *s.begin();
        auto it = s.end();
        it--;
        int s2 = *it;
        set<int> zero;
        set<int> one;
        rep2(i,1,n)
        {
            if(is_clockwise(s1,s2,i))
            {
                one.insert(i);
            }
            else
            {
                zero.insert(i);
            }
        }
        if(size(zero) < size(one)) swap(zero,one);
        if(size(one) == 0)
        {
            edges.pb({s1,s2});
            break;
        }
        else
        {
            s = one;
        }
    }
    if(size(edges) == 0)
    {
        int p = *s.begin();
        rep2(i,1,n)
        {
            if(i == p) continue;
            bool b0 = false;
            bool b1 = false;    
            rep2(k,1,n)
            {
                if(k == i || k == p) continue;
                if(is_clockwise(p,i,k)) b1 = true;
                else b0 = true;
            }
            if(b0 && b1)
            {

            }
            else
            {
                edges.pb({p,i});
                break;
            }
        }
    }
    odw[edges[0].ff] = true;
    odw[edges[0].ss] = true;
    while(true)
    {
        pii pop = edges[size(edges)-1];        
        int p = pop.ss;
        int cur = 1;
        if(p == 1) cur = 2;
        rep2(i,1,n)
        {
            if(i == p || i == cur) continue;
            bool w1 = is_clockwise(pop.ff,p,cur);
            bool w2 = is_clockwise(cur,p,i);
            if(w1 == w2)
            {
                cur = i;
            }
        }
        edges.pb({p,cur});
        if(odw[cur]) break;
        odw[cur] = true;
    }
    give_answer(size(edges));
}

int main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    //random();
    int t = 1;
    //cin >> t;
    while(t--) solve();
}

• Subtask 1: 0 / 15
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 20
• Subtask 5: 0 / 25