Submission #946867

#	Time	Username	Problem	Language	Result	Execution time	Memory
946867		GrindMachine	Roads (CEOI20_roads)	C++17	15 / 100	15 ms	3032 KiB

roads

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a,b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a,b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*



*/

const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

struct frac{
    pll a;

    frac(ll n, ll d){
        ll g = gcd(abs(n),abs(d));
        n /= g, d /= g;
        if(d < 0){
            d = -d;
            n = -n;
        }
        else if(d == 0){
            n = 1;
        }

        a = {n,d};
    }

    bool operator<(const frac &f) const {
        auto [x1,y1] = a;
        auto [x2,y2] = f.a;
        return x1*y2 < x2*y1;
    }
};

void solve(int test_case)
{
    ll n; cin >> n;
    map<frac,vector<pll>> mp;
    frac curr_gradient(1,1);

    rep1(i,n){
        ll x1,y1,x2,y2; cin >> x1 >> y1 >> x2 >> y2;
        frac gradient(y2-y1,x2-x1);
        if(i == 1) curr_gradient = gradient;
        else assert(gradient.a == curr_gradient.a);
        frac y_intercept(y1*(x2-x1)-x1*(y2-y1),x2-x1);
        mp[y_intercept].pb({x1,y1});
        mp[y_intercept].pb({x2,y2});
    }

    vector<array<ll,4>> ans;

    for(auto it = mp.begin(); it != mp.end(); ++it){
        auto &v = it->second;
        sort(all(v));
        // assert(!(sz(v)&1));

        if(it != mp.begin()){
            auto it2 = prev(it);
            ans.pb({it2->second[0].ff,v[0].ff,it2->second[0].ss,v[0].ss});
        }

        for(int i = 1; i < sz(v)-1; i += 2){
            ans.pb({v[i].ff,v[i].ss,v[i+1].ff,v[i+1].ss});
        }
    }

    for(auto [x1,y1,x2,y2] : ans){
        cout << x1 << " " << y1 << " " << x2 << " " << y2 << endl;
    }
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

• Subtask 1: 0 / 0
• Subtask 2: 15 / 15
• Subtask 3: 0 / 15
• Subtask 4: 0 / 15
• Subtask 5: 0 / 15
• Subtask 6: 0 / 40