Submission #812335

#	Time	Username	Problem	Language	Result	Execution time	Memory
812335		penguinman	Fountain Parks (IOI21_parks)	C++17	30 / 100	1511 ms	123228 KiB

parks

#include "parks.h"

#include <bits/stdc++.h>

using std::cin;
using std::cout;
using std::vector;
using std::string;
using ll = int;
using vi = vector<ll>;
using vii = vector<vi>;
using pii = std::pair<ll,ll>;
using std::endl;

#define rep(i,j,k) for(ll i=ll(j); i<ll(k); i++)
#define REP(i,j,k) for(ll i=ll(j); i<=ll(k); i++)
#define per(i,j,k) for(ll i=ll(j); i>=ll(k); i--)
#define ln "\n"
#define pb emplace_back
#define mp std::make_pair
#define all(a) a.begin(),a.end()

int construct_roads(std::vector<int> x, std::vector<int> y) {
    std::map<pii,ll> xy;
    std::map<pii,ll> rev;
    rep(i,0,x.size()) xy[mp(x[i],y[i])] = i;
    ll cnt__ = 0;
    rep(i,0,x.size()){
        vi P = {2,0}, Q = {0,2};
        vi R = {0,1}, S = {1,0};
        rep(j,0,2){
            if(xy.count(mp(x[i]+P[j], y[i]+Q[j]))){
                ll mx = x[i]+P[j]/2;
                ll my = y[i]+Q[j]/2;
                rev[mp(mx+R[j], my+S[j])] = rev[mp(mx-R[j],my-S[j])] = 0;
                cnt__++;
            }
        }
    }
    if(cnt__ != ll(x.size()-1)){
        vector<std::map<ll,ll>> X(7);
        rep(i,0,x.size()){
            X[x[i]][y[i]] = i;
        }
        vi u,v,a,b;
        vi par(x.size());
        rep(i,0,x.size()) par[i] = i;
        std::function<ll(ll)> root = [&](ll now){
            if(par[now] == now) return now;
            return par[now] = root(par[now]);
        };
        for(auto el: X[2]){
            if(X[2].count(el.first+2)){
                u.pb(el.second);
                ll next = X[2][el.first+2];
                v.pb(next);
                a.pb(1);
                b.pb(el.first+1);
                par[root(el.second)] = root(next);
            }
        }
        for(auto el: X[6]){
            if(X[6].count(el.first+2)){
                u.pb(el.second);
                ll next = X[6][el.first+2];
                v.pb(next);
                a.pb(7);
                b.pb(el.first+1);
                par[root(el.second)] = root(next);
            }
        }
        std::set<pii> used;
        for(auto el: X[4]){
            if(X[4].count(el.first+2)){
                ll next = X[4][el.first+2];
                par[root(next)] = root(el.second);
                ll rx = -1, ry = -1;
                if(el.first%4 == 0) rx = 3, ry = el.first+1;
                if(el.first%4 == 2) rx = 5, ry = el.first+1;
                used.insert(mp(rx, ry));
                u.pb(el.second);
                v.pb(next);
                a.pb(rx);
                b.pb(ry);
            }
        }
        for(auto el: X[4]){
            if(X[2].count(el.first)){
                ll next = X[2][el.first];
                if(root(next) != root(el.second)){
                    par[root(next)] = root(el.second);
                    u.pb(el.second);
                    v.pb(next);
                    ll rx = -1, ry = -1;
                    if(!used.count(mp(3,el.first-1))) rx = 3, ry = el.first-1;
                    if(!used.count(mp(3,el.first+1))) rx = 3, ry = el.first+1;
                    assert(rx != -1);
                    a.pb(rx);
                    b.pb(ry);
                    used.insert(mp(rx, ry));
                }
            }
            if(X[6].count(el.first)){
                ll next = X[6][el.first];
                if(root(next) != root(el.second)){
                    par[root(next)] = root(el.second);
                    u.pb(el.second);
                    v.pb(next);
                    ll rx = -1, ry = -1;
                    if(!used.count(mp(5,el.first-1))) rx = 5, ry = el.first-1;
                    if(!used.count(mp(5,el.first+1))) rx = 5, ry = el.first+1;
                    assert(rx != -1);
                    a.pb(rx);
                    b.pb(ry);
                    used.insert(mp(rx, ry));
                }
            }
        }
        if(u.size()+1 == x.size()){
            build(u,v,a,b);
            return 1;
        }
        else return 0;
    }
    ll N = 0;
    vi rx, ry;
    for(auto &el: rev){
        el.second = N++;
        rx.pb(el.first.first);
        ry.pb(el.first.second);
    }
    vii edge(N);
    vii eu(N), ev(N);
    rep(i,0,x.size()){
        vi P = {2,0}, Q = {0,2};
        vi R = {0,1}, S = {1,0};
        rep(j,0,2){
            if(xy.count(mp(x[i]+P[j], y[i]+Q[j]))){
                ll mx = x[i]+P[j]/2;
                ll my = y[i]+Q[j]/2;
                ll nu = rev[mp(mx+R[j], my+S[j])];
                ll nv = rev[mp(mx-R[j],my-S[j])];
                ll nxy = xy[mp(x[i]+P[j], y[i]+Q[j])];
                edge[nu].pb(nv);
                eu[nu].pb(i);
                ev[nu].pb(nxy);
                edge[nv].pb(nu);
                eu[nv].pb(i);
                ev[nv].pb(nxy);
            }
        }
    }
    vi cnt(N);
    rep(i,0,N) cnt[i] = edge[i].size();
    vi u,v,a,b;
    rep(k,0,N){
        if(cnt[k] != 1) continue;
        cnt[k]--;
        ll now = k;
        while(true){
            ll nex = -1;
            rep(i,0,edge[now].size()){
                ll next = edge[now][i];
                if(cnt[next] == 0) continue;
                u.pb(eu[now][i]);
                v.pb(ev[now][i]);
                a.pb(rx[now]);
                b.pb(ry[now]);
                cnt[next]--;
                if(cnt[next] == 1){
                    cnt[next]--;
                    nex = next;
                }
            }
            if(nex == -1) break;
            now = nex;
        }
    }
    rep(i,0,N){
        if(cnt[i] > 2) return 0;
    }
    rep(i,0,N){
        assert(cnt[i] == 0 || cnt[i] == 2);
        if(cnt[i] == 0) continue;
        cnt[i] = 0;
        ll now = i;
        while(true){
            ll val = -1;
            rep(j,0,edge[now].size()){
                ll next = edge[now][j];
                if(cnt[next] == 0) continue;
                u.pb(eu[now][j]);
                v.pb(ev[now][j]);
                a.pb(rx[now]);
                b.pb(ry[now]);
                val = cnt[next];
                cnt[next] = 0;
                now = next;
                break;
            }
            if(val == -1) break;
        }
        rep(j,0,edge[now].size()){
            ll next = edge[now][j];
            if(next != i) continue;
            u.pb(eu[now][j]);
            v.pb(ev[now][j]);
            a.pb(rx[now]);
            b.pb(ry[now]);
        }
    }
    build(u,v,a,b);
    return 1;
}

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 15 / 15
• Subtask 4: 0 / 20
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30