Submission #814197

#	Time	Username	Problem	Language	Result	Execution time	Memory
814197		alvingogo	Fountain Parks (IOI21_parks)	C++17	15 / 100	323 ms	30220 KiB

parks

#include "parks.h"
#include <bits/stdc++.h>
#define fs first
#define sc second
#define p_q priority_queue
using namespace std;

struct DSU{
    vector<int> bo,ss;
    void init(int x){
        bo.resize(x);
        ss.resize(x,1);
        iota(bo.begin(),bo.end(),0);
    }  
    int find(int x){
        return bo[x]==x?x:bo[x]=find(bo[x]);
    }
    int merge(int x,int y){
        x=find(x);
        y=find(y);
        if(x==y){
            return 0;
        }
        bo[x]=y;
        ss[y]+=ss[x];
        return 1;
    }
}dsu;
vector<int> au,av,aa,ab;
void ag(int a,int b,int c,int d){
    au.push_back(a);
    av.push_back(b);
    aa.push_back(c);
    ab.push_back(d);
}
int construct_roads(vector<int> x, vector<int> y) {
    if (x.size() == 1) {
	    build({}, {}, {}, {});
        return 1;
    }
    map<pair<int,int>,int> m;
    int n=x.size();
    for(int i=0;i<n;i++){
        m[pair<int,int>(x[i],y[i])]=i+1;
    }
    dsu.init(n);
    vector<int> up(n,-1),l(n,-1),r(n,-1);
    vector<pair<int,int> > lb;
    for(int p=0;p<n;p++){
        if(m.find(pair<int,int>(x[p],y[p]+2))!=m.end()){
            int a=m[pair<int,int>(x[p],y[p]+2)]-1;
            dsu.merge(a,p);
            if(x[p]==2){
                ag(a,p,1,y[p]+1);
            }
            else if(x[p]==6){
                ag(a,p,7,y[p]+1);
            }
            else{
                up[a]=p;
            }
        }
    }
    for(int p=0;p<n;p++){
        if(x[p]==4){
            lb.push_back({y[p],p});
            if(m.find(pair<int,int>(2,y[p]))!=m.end()){
                int a=m[pair<int,int>(2,y[p])]-1;
                if(dsu.merge(a,p)){
                    l[p]=a;
                }
            }
            if(m.find(pair<int,int>(6,y[p]))!=m.end()){
                int a=m[pair<int,int>(6,y[p])]-1;
                if(dsu.merge(a,p)){
                    r[p]=a;
                }
            }
        }
    }
    if(dsu.ss[dsu.find(0)]!=n){
        return 0;
    }
    sort(lb.begin(),lb.end());
    int flag=0;
    int lst=0;
    for(auto h:lb){
        int i=h.sc;
        if(flag){
            if(up[i]>=0){
                ag(up[i],i,3,h.fs-1);
            }
            assert(l[h.fs]>=0 && r[h.fs]>=0 && up[h.fs]>=0);
            flag=0;
            lst=h.sc;
            continue;
        }
        if(up[i]>=0){
            if(l[i]>=0 && r[i]>=0){
                ag(l[i],i,3,h.fs-1);
                ag(up[i],i,5,h.fs-1);
                ag(r[i],i,5,h.fs+1);
                flag=1;
            }
            else if(l[i]>=0){
                ag(l[i],i,3,h.fs-1);
                ag(up[i],i,5,h.fs-1);
            }
            else if(r[i]>=0){
                ag(r[i],i,5,h.fs-1);
                ag(up[i],i,3,h.fs-1);
            }
            else{
                ag(up[i],i,3,h.fs-1);
            }
        }
        else{
            if(l[i]>=0){
                ag(l[i],i,3,h.fs-1);
            }
            if(r[i]>=0){
                ag(r[i],i,5,h.fs-1);
            }
        }
        lst=h.sc;
    }
    build(au,av,aa,ab);
    return 1;
}

Compilation message (stderr)

parks.cpp: In function 'int construct_roads(std::vector<int>, std::vector<int>)':
parks.cpp:86:9: warning: variable 'lst' set but not used [-Wunused-but-set-variable]
   86 |     int lst=0;
      |         ^~~

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