Submission #951235

#	Time	Username	Problem	Language	Result	Execution time	Memory
951235		Trisanu_Das	Fountain Parks (IOI21_parks)	C++17	70 / 100	521 ms	71060 KiB

parks

#include "parks.h"
#include <bits/stdc++.h>
using namespace std;
// trans rights
#define ll long long
#define f first
#define s second
#define endl '\n'
#define all(x) begin(x), end(x)
int n;
vector<int> u, v, a, b;
map<pair<int, int>, int> mp;
set<pair<int, int>> done;
 
vector<pair<int, int>> dirs = {{0, 2}, {2, 0}, {0, -2}, {-2, 0}};
vector<pair<int, int>> bloc[2] = {{{-1, 1}, {1, 1}, {1, -1}, {-1, -1}}, {{1, 1}, {1, -1}, {-1, -1}, {-1, 1}}};
 
void dfs(int x, int y, int ldir = 0) {
    done.insert({x, y});
    for (int i = 0; i < 4; i++) {
        int ndir = (ldir + 3 + i) % 4;
        int nx = x + dirs[ndir].f;
        int ny = y + dirs[ndir].s;
        if (mp.find({nx, ny}) == mp.end()) continue;
        if (done.find({nx, ny}) != done.end()) continue;
 
        int tx = x + bloc[0][ndir].f;
        int ty = y + bloc[0][ndir].s;
        if (done.find({tx, ty}) == done.end()) {
            u.push_back(mp[{x, y}]);
            v.push_back(mp[{nx, ny}]);
            done.insert({tx, ty});
            a.push_back(tx);
            b.push_back(ty);
            dfs(nx, ny, ndir);
            continue;
        }
 
        tx = x + bloc[1][ndir].f;
        ty = y + bloc[1][ndir].s;
        if (done.find({tx, ty}) == done.end()) {
            u.push_back(mp[{x, y}]);
            v.push_back(mp[{nx, ny}]);
            done.insert({tx, ty});
            a.push_back(tx);
            b.push_back(ty);
            dfs(nx, ny, ndir);
        }
    }
}
 
int construct_roads(vector<int> xs, vector<int> ys) {
    n = xs.size();
    for (int i = 0; i < n; i++) {
        mp[{xs[i], ys[i]}] = i;
    }
    dfs(xs[0], ys[0]);
    if (u.size() == n - 1) {
        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:58:18: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   58 |     if (u.size() == n - 1) {
      |         ~~~~~~~~~^~~~~~~~

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