Submission #1021045

#	Time	Username	Problem	Language	Result	Execution time	Memory
1021045		mdn2002	Fountain Parks (IOI21_parks)	C++17	5 / 100	549 ms	113968 KiB

parks

/*
Mayoeba Yabureru
*/
#include "parks.h"
#include<bits/stdc++.h>
using namespace std;
static vector<int> _u, _v, _a, _b;



int construct_roads(vector<int> x, vector<int> y) {
    int n = x.size();
    vector<vector<int>> gr(n + 1);
    x.insert(x.begin(), 0);
    y.insert(y.begin(), 0);
    map<pair<int, int>, int> mp;
    for (int i = 1; i <= n; i ++) mp[{x[i], y[i]}] = i;
    vector<int> u, v, a, b;

    map<pair<pair<int, int>, pair<int, int>>, int> connected;
    map<pair<int, int>, int> taken;
    for (int i = 1; i <= n; i ++) {
        if (x[i] == 2 && mp[{x[i], y[i] + 2}]) {
            connected[{{x[i], y[i]}, {x[i], y[i] + 2}}] = 1;
            u.push_back(i), v.push_back(mp[{x[i], y[i] + 2}]);
            a.push_back(x[i] - 1), b.push_back(y[i] + 1);
            taken[{x[i] - 1, y[i] + 1}] = 1;
            gr[i].push_back(mp[{x[i], y[i] + 2}]);
            gr[mp[{x[i], y[i] + 2}]].push_back(i);
        }
        else if (x[i] == 6 && mp[{x[i], y[i] + 2}]) {
            connected[{{x[i], y[i]}, {x[i], y[i] + 2}}] = 1;
            u.push_back(i), v.push_back(mp[{x[i], y[i] + 2}]);
            a.push_back(x[i] + 1), b.push_back(y[i] + 1);
            taken[{x[i] + 1, y[i] + 1}] = 1;
            gr[i].push_back(mp[{x[i], y[i] + 2}]);
            gr[mp[{x[i], y[i] + 2}]].push_back(i);
        }
        else if (x[i] == 4 && mp[{x[i], y[i] + 2}]) {
            connected[{{x[i], y[i]}, {x[i], y[i] + 2}}] = 1;
            u.push_back(i), v.push_back(mp[{x[i], y[i] + 2}]);

            if (y[i] % 4 == 2) a.push_back(x[i] + 1);
            else a.push_back(x[i] - 1);
            b.push_back(y[i] + 1);
            taken[{a.back(), b.back()}] = 1;

            gr[i].push_back(mp[{x[i], y[i] + 2}]);
            gr[mp[{x[i], y[i] + 2}]].push_back(i);
        }
    }
    for (int i = 1; i <= n; i ++) {
        if (x[i] == 2 && mp[{x[i] + 2, y[i]}]) {
            if (connected[{{x[i], y[i] - 2}, {x[i] + 2, y[i] - 2}}] == 1) continue;
            u.push_back(i), v.push_back(mp[{x[i] + 2, y[i]}]);
            if (taken[{x[i] + 1, y[i] + 1}] == 0) {
                a.push_back(x[i] + 1), b.push_back(y[i] + 1);
                taken[{x[i] + 1, y[i] + 1}] = 1;
            }
            else if (taken[{x[i] + 1, y[i] - 1}] == 0) {
                a.push_back(x[i] + 1), b.push_back(y[i] - 1);
                taken[{x[i] + 1, y[i] - 1}] = 1;
            }
            else assert(0);
            connected[{{x[i], y[i]}, {x[i] + 2, y[i]}}] = 1;

            gr[i].push_back(mp[{x[i] + 2, y[i]}]);
            gr[mp[{x[i] + 2, y[i]}]].push_back(i);
        }
        else if (x[i] == 6 && mp[{x[i] - 2, y[i]}]) {
            if (connected[{{x[i], y[i] - 2}, {x[i] - 2, y[i] - 2}}] == 1) continue;
            u.push_back(i), v.push_back(mp[{x[i] - 2, y[i]}]);
            if (taken[{x[i] - 1, y[i] + 1}] == 0) {
                a.push_back(x[i] - 1), b.push_back(y[i] + 1);
                taken[{x[i] - 1, y[i] + 1}] = 1;
            }
            else if (taken[{x[i] - 1, y[i] - 1}] == 0) {
                a.push_back(x[i] - 1), b.push_back(y[i] - 1);
                taken[{x[i] - 1, y[i] + 1}] = 1;
            }
            else assert(0);
            connected[{{x[i], y[i]}, {x[i] - 2, y[i]}}] = 1;

            gr[i].push_back(mp[{x[i] - 2, y[i]}]);
            gr[mp[{x[i] - 2, y[i]}]].push_back(i);
        }
    }
    for (int i = 0; i < u.size(); i ++) {
        u[i] --;
        v[i] --;
    }
    int num = 0;
    vector<int> vis(n + 1);
    function<void(int)> go = [&] (int x) {
        num ++;
        vis[x] = 1;
        for (auto u : gr[x]) {
            if (vis[u]) continue;
            go(u);
        }
    };
    go(1);

    if (num == n) {
        build(u, v, a, b);
        return 1;
    }
    return 0;
}

Compilation message (stderr)

parks.cpp: In function 'int construct_roads(std::vector<int>, std::vector<int>)':
parks.cpp:88:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   88 |     for (int i = 0; i < u.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