Submission #1053268

#	Time	Username	Problem	Language	Result	Execution time	Memory
1053268		aykhn	Fountain Parks (IOI21_parks)	C++17	5 / 100	677 ms	63788 KiB

parks

#include "parks.h"
#include <bits/stdc++.h>

using namespace std;

int A[4] = {0, 0, 2, -2};
int B[4] = {2, -2, 0, 0};
array<int, 2> ben[4][2] = {{{-1, 1}, {1, 1}}, {{-1, -1}, {1, -1}}, {{1, 1}, {1, -1}}, {{-1, 1}, {-1, -1}}};

struct DSU
{
    vector<int> e;
    void init(int n)
    {
        e.assign(n, -1);
    }
    int get(int x)
    {
        if (e[x] < 0) return x;
        return e[x] = get(e[x]);
    }
    void unite(int x, int y)
    {
        x = get(x), y = get(y);
        if (x == y) return;
        if (e[x] > e[y]) swap(x, y);
        e[x] += e[y];
        e[y] = x;
    }
};

int construct_roads(vector<int> X, vector<int> Y) 
{
    map<array<int, 2>, int> mp, us;
    for (int i = 0; i < X.size(); i++) mp[{X[i], Y[i]}] = i + 1;
    vector<int> u, v, a, b;
    DSU dsu;
    dsu.init(X.size());
    for (int i = 0; i < X.size(); i++)
    {
        int x = X[i], y = Y[i];
        for (int k = 0; k < 4; k++)
        {
            int x1 = x + A[k], y1 = y + B[k];
            if (!mp[{x1, y1}] || mp[{x1, y1}] < i + 1) continue;
            u.push_back(i), v.push_back(mp[{x1, y1}] - 1);
            dsu.unite(i, mp[{x1, y1}] - 1);
            for (array<int, 2> &j : ben[k])
            {
                int a1 = x + j[0], b1 = y + j[1];
                if (!us[{a1, b1}])
                {
                    a.push_back(a1);
                    b.push_back(b1);
                    break;
                }
            }
            assert(a.size() == u.size());
        }
    }
    for (int i = 0; i < X.size(); i++)
    {
        if (dsu.get(i) != dsu.get(0)) 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:35:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |     for (int i = 0; i < X.size(); i++) mp[{X[i], Y[i]}] = i + 1;
      |                     ~~^~~~~~~~~~
parks.cpp:39:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   39 |     for (int i = 0; i < X.size(); i++)
      |                     ~~^~~~~~~~~~
parks.cpp:61:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   61 |     for (int i = 0; i < X.size(); i++)
      |                     ~~^~~~~~~~~~

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