Submission #1033992

#	Time	Username	Problem	Language	Result	Execution time	Memory
1033992		hotboy2703	Fountain Parks (IOI21_parks)	C++17	100 / 100	208 ms	28840 KiB

parks

#include "parks.h"

#include<bits/stdc++.h>
using ll = int;
using namespace std;
#define pll pair <ll,ll>
#define fi first
#define se second
#define MP make_pair
#define sz(a) (ll((a).size()))
#define MASK(i) (1LL<<(i))
#define BIT(mask,i) (((mask) >> (i))&1)
struct point{
    ll x,y,id;
    point(ll x1 = 0,ll y1 = 0,ll id1 = 0):x(x1),y(y1),id(id1){}
    bool operator < (const point &p)const {
        return MP(x,y) < MP(p.x,p.y);
    }
};
const ll MAXN = 2e5+100;
ll dsu[MAXN];
ll f(ll x){
    if (dsu[x] < 0)return x;
    return (dsu[x] = f(dsu[x]));
}
bool join(ll x,ll y){
    x = f(x),y = f(y);
    if (x==y)return 0;
    dsu[x] += dsu[y];
    dsu[y] = x;
    return 1;
}
int construct_roads(std::vector<int> x, std::vector<int> y) {
    ll n = sz(x);
    vector <point> a(n);
    
    for (ll i = 0;i < n;i ++){
        dsu[i] = -1;
        a[i] = {x[i],y[i],i};
    }
    sort(a.begin(),a.end());
    vector <int> U, V, A, B;
    set <pll> bench;
    auto add = [&](ll u,ll v, ll x,ll y){
        // cout<<u<<' '<<v<<endl;
        if (join(u,v)==0)return;
        U.push_back(u);
        V.push_back(v);
        A.push_back(x);
        B.push_back(y);
        bench.insert(MP(x,y));
    };
    auto id = [&](pll x){
        auto tmp = lower_bound(a.begin(),a.end(),point(x.fi,x.se,0));
        if (tmp != a.end() && (*tmp).x==x.fi&&(*tmp).y==x.se)return (*tmp).id;
        else return -1;
    };
    for (ll i = 0;i < n;i ++){
        // cout<<i<<endl;
        if (((a[i].x + a[i].y)/2)&1){
            if (bench.find(MP(a[i].x + 1,a[i].y - 1)) == bench.end() && id(MP(a[i].x,a[i].y-2)) != -1){
                add(a[i].id,id(MP(a[i].x,a[i].y-2)),a[i].x+1,a[i].y-1);
            }
            if (bench.find(MP(a[i].x - 1,a[i].y - 1)) == bench.end() && id(MP(a[i].x-2,a[i].y)) != -1){
                add(a[i].id,id(MP(a[i].x-2,a[i].y)),a[i].x-1,a[i].y-1);
            }
        }
        else{
            // cout<<i<<endl;
            if (bench.find(MP(a[i].x - 1,a[i].y - 1)) == bench.end() && id(MP(a[i].x,a[i].y-2)) != -1){
                add(a[i].id,id(MP(a[i].x,a[i].y-2)),a[i].x-1,a[i].y-1);
            }
            if (bench.find(MP(a[i].x - 1,a[i].y + 1)) == bench.end() && id(MP(a[i].x-2,a[i].y)) != -1){
                add(a[i].id,id(MP(a[i].x-2,a[i].y)),a[i].x-1,a[i].y+1);
            }
        }
    }
    {
        if (dsu[f(0)] != -n)return 0;
        build(U, V, A, B);
        return 1;
    }
}

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