Submission #1219043

#	Time	Username	Problem	Language	Result	Execution time	Memory
1219043		brinton	Fountain Parks (IOI21_parks)	C++20	45 / 100	290 ms	51336 KiB

parks

#include "parks.h"
#include <bits/stdc++.h>
using namespace std;

int construct_roads(vector<int> x, vector<int> y) {
    int N = x.size();
    map<pair<int,int>,int> mp;
    for(int i = 0;i < N;i++) mp[{x[i],y[i]}] = i;
    vector<int> vis(N,false);

    int dx[4] = {0,2,-2,0};
    int dy[4] = {2,0,0,-2};
    vector<int> u,v,a,b;
    auto add_road = [&](int aidx,int bidx){
        int midx = (x[aidx]+x[bidx])/2;
        int midy = (y[aidx]+y[bidx])/2;
        if(x[aidx] == x[bidx]){
            // vertical
            if((midy/2)%2 == (midx/2)%2){
                midx++;
            }else{
                midx--;
            }
        }else{
            // horizontal
            if((midx/2)%2 == (midy/2)%2){
                midy--;
            }else{
                midy++;
            }
        }
        u.push_back(aidx);
        v.push_back(bidx);
        a.push_back(midx);
        b.push_back(midy);
    };
    function<void(int)> dfs = [&](int idx){
        // cout << "!" << idx << endl;
        vis[idx] = true;
        int cx = x[idx],cy = y[idx];
        for(int d = 0;d < 4;d++){
            int nx = cx+dx[d];
            int ny = cy+dy[d];
            if(!mp.count({nx,ny})) continue;
            int nidx = mp[{nx,ny}];
            if(vis[nidx]) continue;
            add_road(idx,nidx);
            dfs(nidx);
        }
    };
    dfs(0);
    for(auto &i:vis){
        if(!i) return 0;
    }
    build(u,v,a,b);
    return true;
}

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