Submission #564576

#	Time	Username	Problem	Language	Result	Execution time	Memory
564576		1zaid1	Building Skyscrapers (CEOI19_skyscrapers)	C++17	0 / 100	281 ms	477412 KiB

skyscrapers

#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define int long long
typedef long long ll;
const int M = 2e7 + 5, MOD = 1e9+7;
struct point {int x, y, i;};
int vis[M], cnt, nig[M];
vector<int> node[M];

vector<int> ans;
void bfs(int s) {
    deque<int> q;
    q.push_back(s);
    vis[s] = true;
    while (!q.empty()) {
        int t = q.front();
        q.pop_back();
        int pp = 0;
        for (int i:node[t]) pp += vis[i];
        if (pp >= 2 && !vis[nig[t]]) {
            q.push_front(t);
            nig[t] = true;
        } else {
            ans.push_back(t);
            cnt++;
            for (int i:node[t]) {
                if (!vis[i]) {
                    vis[i] = true;
                    q.push_back(i);
                }
            }
        }
    }
}

signed main() {
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    srand(time(0));
    
    int n, t;
    cin >> n >> t;

    vector<point> v(n);
    for (auto&i:v) cin >> i.x >> i.y;
    int ind = 1; for (auto&i:v) i.i = ind++;

    vector<point> p;
    sort(v.begin(), v.end(), [](point a, point b){if (a.y == b.y) return a.x < b.x; return a.y < b.y;});
    for (int i = 0; i < n; i++) {
        while (i < n && (!i || v[i].y == v[i-1].y)) {
            p.push_back(v[i++]);
        }
 
        for (int j = 1; j < p.size(); j++) {
            if (p[j-1].x+1 == p[j].x) {
                node[p[j].i].push_back(p[j-1].i);
                node[p[j-1].i].push_back(p[j].i);
            }
        }
 
        p.clear();
        p.push_back(v[i]);
    }
 
    p.clear();
    sort(v.begin(), v.end(), [](point a, point b){if (a.x == b.x) return a.y < b.y; return a.x < b.x;});
    for (int i = 0; i < n; i++) {
        while (i < n && (!i || v[i].x == v[i-1].x)) {
            p.push_back(v[i++]);
        }
 
        for (int j = 1; j < p.size(); j++) {
            if (p[j-1].y+1 == p[j].y) {
                node[p[j].i].push_back(p[j-1].i);
                node[p[j-1].i].push_back(p[j].i);
            }
        }
 
        p.clear();
        p.push_back(v[i]);
    }
 
    p.clear();
    sort(v.begin(), v.end(), [](point a, point b){if ((a.x+a.y) == (b.x+b.y)) return a.x < b.x; return a.x+a.y < b.x+b.y;});
    for (int i = 0; i < n; i++) {
        while (i < n && (!i || (v[i].x+v[i].y) == (v[i-1].x+v[i-1].y))) {
            p.push_back(v[i++]);
        }
 
        for (int j = 1; j < p.size(); j++) {
            if (p[j-1].x+1 == p[j].x) {
                node[p[j].i].push_back(p[j-1].i);
                node[p[j-1].i].push_back(p[j].i);
            }
        }
 
        p.clear();
        p.push_back(v[i]);
    }
 
    p.clear();
    sort(v.begin(), v.end(), [](point a, point b){if ((a.x-a.y) == (b.x-b.y)) return a.x < b.x; return a.x-a.y < b.x-b.y;});
    for (int i = 0; i < n; i++) {
        while (i < n && (!i || (v[i].x-v[i].y) == (v[i-1].x-v[i-1].y))) {
            p.push_back(v[i++]);
        }
 
        for (int j = 1; j < p.size(); j++) {
            if (p[j-1].x+1 == p[j].x) {
                node[p[j].i].push_back(p[j-1].i);
                node[p[j-1].i].push_back(p[j].i);
            }
        }
 
        p.clear();
        p.push_back(v[i]);
    }

    bfs(1);
    if (cnt == n) {
        cout << "YES" << endl;
        for (int i:ans) cout << i << endl;
    } else cout << "NO" << endl;

    return 0;
}

/*
3 2
0 0
0 1
0 2
*/

Compilation message (stderr)

skyscrapers.cpp: In function 'int main()':
skyscrapers.cpp:55:27: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<point>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   55 |         for (int j = 1; j < p.size(); j++) {
      |                         ~~^~~~~~~~~~
skyscrapers.cpp:73:27: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<point>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   73 |         for (int j = 1; j < p.size(); j++) {
      |                         ~~^~~~~~~~~~
skyscrapers.cpp:91:27: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<point>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   91 |         for (int j = 1; j < p.size(); j++) {
      |                         ~~^~~~~~~~~~
skyscrapers.cpp:109:27: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<point>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  109 |         for (int j = 1; j < p.size(); j++) {
      |                         ~~^~~~~~~~~~

• Subtask 1: 0 / 8
• Subtask 2: 0 / 14
• Subtask 3: 0 / 12
• Subtask 4: 0 / 17
• Subtask 5: 0 / 20
• Subtask 6: 0 / 10
• Subtask 7: 0 / 19