Submission #598644

#	Time	Username	Problem	Language	Result	Execution time	Memory
598644		definitelynotmee	Fountain Parks (IOI21_parks)	C++17	Compilation error	0 ms	0 KiB

parks

#include "parks.h"
#include<bits/stdc++.h>
using namespace std;
#define ff first
#define ss second
#define all(x) x.begin(), x.end()
using ll = long long;
using pii = pair<int,int>;
using pll = pair<ll,ll>;
template<typename t>
using matrix = vector<vector<t>>;


int construct_roads(std::vector<int> x, std::vector<int> y) {
    if (x.size() == 1) {
	build({}, {}, {}, {});
        return 1;
    }
    int n = x.size();
    std::vector<int> u, v, a(n-1), b(n-1);

    int dx[]{1,0,-1,0};
    int dy[]{0,1,0,-1};

    vector<int> pai(n);
    int comp = n;
    iota(all(pai),0);

    auto find =[&](int id, auto f){
        if(pai[id] == id)
            return id;
        return pai[id] = f(pai[id],f);
    };
    auto onion =[&](int a, int b){
        int pa = find(a,find);
        int pb = find(b,find);
        if(pa != pb){
            comp--;
            u.push_back(a);
            v.push_back(b);
        }
        pai[pa] = pb;
    };
    map<pii,int> fount;
    map<pii,int> road;


    for(int i = 0; i < n; i++)
        fount[{x[i],y[i]}] = i;


    for(int i = 0; i < n; i++){
        for(int j = 0; j < 4; j++){
            int xi = x[i] + dx[j]*2, yi = y[i]+dy[j]*2;
            if(fount.count({xi,yi}))
                onion(i,fount[{xi,yi}]);
        }
    }

    if(comp > 1)
        return 0;

    for(int i = 0; i < n; i++){
        int cx = (x[u[i]]+x[v[i]])>>1, cy = (y[u[i]]+y[v[i]])>>1;
        road[{cx,cy}] = i;
    }

    auto adj =[&](int x, int y){
        vector<int> ret;
        for(int i = 0; i < 4; i++){
            int xi = x + dx[i], yi = y + dy[i];
            if(roads.count({xi,yi}))
                ret.push_back(roads[{xi,yi}]);
        }
        return ret;
    };

    vector<int> st;
    vector<int> check(n-1);

    for(int i = 0; i < n-1; i++){
        int cx = (x[u[i]]+x[v[i]])>>1, cy = (y[u[i]]+y[v[i]])>>1;
        if(adj(cx,cy).size() == 1)
            st.push_back(i);
    }

    set<pii> bench;

    while(!st.empty()){
        int cur = st.back();
        st.pop_back();
        if(check[cur])
            continue;
        check[cur] = 1;
        int cx = (x[u[cur]]+x[v[cur]])>>1, cy = (y[u[cur]]+y[v[cur]])>>1;
        bool ok = 0;
        for(int j = 0; j < 4; j++){
            int xi = cx + dx[j], yi = cy+dy[j];
            if(!((xi&1)&&(yi&1)))
                continue;
            if(!bench.count({xi,yi})){
                a[cur] = xi;
                b[cur] =yi;
                bench.insert({xi,yi});
                ok = 1;
                break;
            }
        }
        if(!ok)
            return 0;
        road.erase({cx,cy});
        vector<int> call = adj(a[cur],b[cur]);
        for(int i : call)
            if(!check[i])
                st.push_back(i);
    }

    for(int i : o){
        if(check[i])
            continue;
        int cx = (x[u[i]]+x[v[i]])>>1, cy = (y[u[i]]+y[v[i]])>>1;
        bool ok = 0;
        for(int j = 0; j < 4; j++){
            int xi = cx + dx[j], yi = cy+dy[j];
            if(!((xi&1)&&(yi&1)))
                continue;
            if(!bench.count({xi,yi})){
                a[i] = xi;
                b[i] =yi;
                bench.insert({xi,yi});
                ok = 1;
                break;
            }
        }
        if(!ok)
            return 0;
    }
    build(u,v,a,b);

    return 1;
}

Compilation message (stderr)

parks.cpp: In lambda function:
parks.cpp:72:16: error: 'roads' was not declared in this scope; did you mean 'road'?
   72 |             if(roads.count({xi,yi}))
      |                ^~~~~
      |                road
parks.cpp: In function 'int construct_roads(std::vector<int>, std::vector<int>)':
parks.cpp:118:17: error: 'o' was not declared in this scope
  118 |     for(int i : o){
      |                 ^