Submission #944063

#	Time	Username	Problem	Language	Result	Execution time	Memory
944063		vjudge1	Building Skyscrapers (CEOI19_skyscrapers)	C++17	0 / 100	161 ms	7944 KiB

skyscrapers

#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx,avx2,fma")
#include <bits/stdc++.h>
 
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define int long long
#define rnd(l, r) uniform_int_distribution<int>(l, r)(rng)
 
using namespace std;
 
void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);} 
int pow(int a,int b,int m){int ans=1;while(b){if(b&1){ans=(ans*a)%m;}b>>=1;a=(a*a)%m;}return ans;}
int binpow(int a,int b){int ans=1;while(b){if(b&1){ans=(ans*a);}b>>=1;a=(a*a);}return ans;}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
 
const int N = 1e5 + 100, mxc = 105, inf = 1e18, MX = 1e5 + 10;

int dx[8] = {1, 0, 0, -1, 1, 1, -1, -1};
int dy[8] = {0, 1, -1, 0, 1, -1, 1, -1};
int x[N], y[N];

map <pair <int,int>, int> mp;

main(){
	iostream::sync_with_stdio(false);	
    cin.tie(nullptr);
    cout.tie(nullptr);
	int t, n;
	cin >> n >> t;
	for(int i = 1; i <= n; i++){
		cin >> x[i] >> y[i];
		mp[{x[i], y[i]}] = i;
	}
	
	int f = 1;
	
	for(int i = 1;  i <= n; i++){
		if(x[f] > x[i])f = i;
	}
	set <pair <int, int> > st;
	st.insert({x[f], f});
	vector <int> was(n + 1);
	vector <int> ans;
	while(!st.empty()){
		int ind = st.begin() -> ss;
		ans.pb(ind);
		was[ind] = 1;
		st.erase(st.begin());
		for(int i = 0; i < 8; i++){
			if(mp.count({x[ind] + dx[i], y[ind] + dy[i]})){
				if(was[mp[{x[ind] + dx[i], y[ind] + dy[i]}]] == 1)continue;
				st.insert({x[ind] + dx[i], mp[{x[ind] + dx[i], y[ind] + dy[i]}]});
			}
		}
	}
	if(ans.size() != n){
		cout << "NO\n";
		return 0;
	}
	cout << ans.size() << endl;
	for(auto x : ans)
		cout << x <<" ";
}	
/*
 * Before implementing the problem:
	
	Do I understand the problem correctly?
	Which places are tricky? What do I need to remember to implement them correctly?
	Which place is the heaviest by implementation? Can I do it simpler?
	Which place is the slowest? Where do I need to be careful about constant factors and where I can choose slower but simpler implementation?
	----------------------------------
	If not AC:
 
	Did you remember to do everything to handle the tricky places you thought about before?
	Is the solution correct?
	Do I understand the problem correctly?
	----------------------------------
	If you have a test on which the solution gives wrong answer:
 
	Is the solution doing what it was supposed to do?
	Is the problem in the code or in the idea?
*/

Compilation message (stderr)

skyscrapers.cpp:28:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   28 | main(){
      | ^~~~
skyscrapers.cpp: In function 'int main()':
skyscrapers.cpp:60:16: warning: comparison of integer expressions of different signedness: 'std::vector<long long int>::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
   60 |  if(ans.size() != n){
      |     ~~~~~~~~~~~^~~~
skyscrapers.cpp: In function 'void fp(std::string)':
skyscrapers.cpp:15:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 | void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
skyscrapers.cpp:15:70: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 | void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
      |                                                               ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• 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