Submission #896371

#	Time	Username	Problem	Language	Result	Execution time	Memory
896371		abcvuitunggio	Fountain Parks (IOI21_parks)	C++17	55 / 100	569 ms	54256 KiB

parks

#include "parks.h"
#include <bits/stdc++.h>
using namespace std;
int n,order[200001],p[200001],cnt;
map <int, int> mp[300001];
vector <int> px,py;
int f(int i){
    return (p[i]==i?i:p[i]=f(p[i]));
}
bool unite(int i, int j){
    i=f(i);
    j=f(j);
    if (i==j)
        return false;
    p[j]=i;
    return true;
}
int construct_roads(vector <int> x, vector <int> y){
    vector <int32_t> u,v,a,b;
    n=x.size();
    for (int i=0;i<n;i++)
        mp[x[i]][y[i]]=i;
    iota(order,order+n,0);
    px=x,py=y;
    sort(order,order+n,[](int i, int j){return make_pair(px[i],py[i])<make_pair(px[j],py[j]);});
    for (int i=0;i<n;i++){
        if (mp[x[i]-2].count(y[i])){
            int X=x[i]-1,Y=(x[i]%4?(y[i]+3)/4*4-1:y[i]/4*4+1);
            if (!mp[X].count(Y)){
                u.push_back(i);
                v.push_back(mp[x[i]-2][y[i]]);
                a.push_back(X);
                b.push_back(Y);
                mp[X][Y]=1;
            }
        }
        if (mp[x[i]].count(y[i]-2)){
            int X=(y[i]%4?x[i]/4*4+1:(x[i]+3)/4*4-1),Y=y[i]-1;
            if (!mp[X].count(Y)){
                u.push_back(i);
                v.push_back(mp[x[i]][y[i]-2]);
                a.push_back(X);
                b.push_back(Y);
                mp[X][Y]=1;
            }
        }
    }
    iota(p,p+n,0);
    for (int i=0;i<u.size();i++)
        cnt+=unite(u[i],v[i]);
    if (cnt<n-1)
        return 0;
    build(u,v,a,b);
    return 1;
}

Compilation message (stderr)

parks.cpp: In function 'int construct_roads(std::vector<int>, std::vector<int>)':
parks.cpp:49:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   49 |     for (int i=0;i<u.size();i++)
      |                  ~^~~~~~~~~

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