Submission #1050741

#	Time	Username	Problem	Language	Result	Execution time	Memory
1050741		amine_aroua	Fountain Parks (IOI21_parks)	C++17	5 / 100	256 ms	51880 KiB

parks

#include "parks.h"
#include<bits/stdc++.h>
using namespace std;
vector<vector<int>> adj;
vector<bool> vis;
const int MAX_X = 200000;
void dfs(int i)
{
    if(vis[i])
        return;
    vis[i] = 1;
    for(auto j : adj[i])
    {
        dfs(j);
    }
}
int mn , mx , cur_x;
void dfs_comp(int i , vector<int> &y)
{
    if(vis[i])
        return ;
    vis[i] = 1;
    mn = min(mn , y[i]);
    mx = max(mx , y[i]);
    for(auto j : adj[i])
    {
        dfs_comp(j , y);
    }
}
void add_edge(int u , int v)
{
    adj[u].push_back(v);
    adj[v].push_back(u);
}
int construct_roads(std::vector<int> x, std::vector<int> y) {
    int n= (int)x.size();
    adj.assign(n , {});
    vis.assign(n , 0);
    vector<int> u , v , a , b;
    map<pair<int, int> , int> idx;
    
    for(int i = 0 ; i <n ; i++)
    {
        idx[{x[i] , y[i]}] = i;
    }
    for(int i = 0 ; i < n ;i++)
    {
        if(idx.count({x[i] , y[i] + 2}))
        {
            u.push_back(i);
            v.push_back(idx[{x[i] , y[i] + 2}]);
            add_edge(u.back() , v.back());
            b.push_back(y[i] + 1);
            a.push_back(x[i] - 1);
        }
    }
    vector<vector<int>> comp(MAX_X + 1);
    for(int i = 0 ; i < n ;i++)
    {
        if(vis[i])
            continue;
        cur_x = x[i];
        mn = 1e9;
        mx = -1e9;
        dfs_comp(i , y);
        comp[cur_x].push_back(mn);
        if(mx != mn)
            comp[cur_x].push_back(mx);
    }
    for(int i = 2  ;i <= MAX_X ; i+=2)
    {
        sort(comp[i].begin() , comp[i].end());
    }
    for(int i = 4 ; i <= MAX_X ; i+=2)
    {
        for(int j = 0 ; j < (int)comp[i].size() ; j++)
        {
            int val = comp[i][j];
            if(binary_search(comp[i - 2].begin() , comp[i - 2].end() , val))
            {
                u.push_back(idx[{i,val}]);
                v.push_back(idx[{i - 2 , val}]);
                add_edge(u.back() , v.back());
                a.push_back(i - 1);
                if(j % 2 == 0)
                    b.push_back(val - 1);
                else
                    b.push_back(val + 1);
            }
        }
    }
    vis.assign(n , 0);
    dfs(0);
    for(int i = 0 ; i < n ; i++)
    {
        if(!vis[i])
        {
            return 0;
        }
    }
    build(u , v , a , b);
    return 1;
}

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