Submission #564611

#	Time	Username	Problem	Language	Result	Execution time	Memory
564611		birthdaycake	Building Skyscrapers (CEOI19_skyscrapers)	C++17	0 / 100	560 ms	1048576 KiB

skyscrapers

#include<bits/stdc++.h>
#define int long long
#define endl '\n'
#define mod 1000000007
#define boost ios_base::sync_with_stdio(false), cin.tie(NULL);
using namespace std;
 
 
 
 
int grid[5001][5001],vs[5001][5001],w[5001][5001];
 
 
int x[] = {-1,-1,-1,0,1,1,1,0}, y[] = {-1,0,1,1,1,0,-1,-1};
int xx[] = {0,0,1,-1}, yy[] = {1,-1,0,0};
vector<pair<int,int>>p;
vector<pair<int,int>>nxt;
vector<int>ans;
int n;
 
 
 
bool cmp(int* a, int *b){
    return *a < *b;
}
 
 
bool check(){
    vector<pair<int,int>>b;
    b.push_back({p[0].first,p[0].second});
    set<pair<int,int>>c,d;
    for(int i = 1; i < n; i++){
        d.insert({p[i].first,p[i].second});
    }
    int j = 0;
    while(j < b.size()){
        for(int k = 0; k < 8; k++){
            int nx = b[j].first + x[k], ny = b[j].second + y[k];
            if(d.count({nx,ny})){
                d.erase({nx,ny});
                b.push_back({nx,ny});
            }
        }
        j++;
    }
    return d.empty();
}
 
 


void dfs(int a, int b){
    vs[a][b] = 1;
    if(grid[a][b]){
        nxt.push_back({a,b});
        return;
    }
    for(int k = 0; k < 4; k++){
        int aa = a + xx[k], bb = b + yy[k];
        if(aa < 0 || bb < 0 || aa >= 2 * n || bb >= 2 * n || vs[aa][bb]) continue;
        dfs(aa,bb);
    }
}
signed main(){
    boost;
    
    
    
    int t, cnt = 0; cin >> n >> t;
    vector<int*>d;
    set<int>tt; map<int,int>bb;
    for(int i = 0; i < n; i++){
        int x,y;
        cin >> x >> y;
        p.push_back({x,y});
        tt.insert(x); tt.insert(y);
    }
    if(!check()){
        cout << "NO";
        return 0;
    }
    for(auto s:tt){
        bb[s] = cnt++;
    }
    for(int i = 0; i < n; i++){
        p[i].first = bb[p[i].first];
        p[i].second = bb[p[i].second];
        grid[p[i].first][p[i].second] = 1;
        w[p[i].first][p[i].second] = i;
    }
    for(int i = 0; i < 2 * n; i++){
        for(int j = 0; j < 2 * n; j++){
            if(i == 0 || j == 0 || i == 2 * n - 1 || j == 2 * n - 1){
                if(!vs[i][j]){
                    dfs(i,j);
                }
            }
        }
    }
    while(nxt.size()){
        vector<pair<int,int>>b;
        set<pair<int,int>>s;
        b.push_back({nxt[0].first,nxt[0].second});
        ans.push_back(w[nxt[0].first][nxt[0].second]);
        for(int i = 1; i < nxt.size(); i++){
            s.insert({nxt[i].first,nxt[i].second});
        }
        int j = 0;
        while(j < b.size()){
            for(int k = 0; k < 8; k++){
                int nx = b[j].first + x[k], ny = b[j].second + y[k];
                if(s.count({nx,ny})){
                    s.erase({nx,ny});
                    b.push_back({nx,ny});
                    ans.push_back(w[nx][ny]);
                }
            }
            j++;
        }
        nxt.clear();
        for(int i = 0; i < b.size(); i++){
            for(int k = 0; k < 4; k++){
                int aa = b[i].first + xx[k], bb = b[i].second + yy[k];
                if(aa < 0 || bb < 0 || aa >= 2 * n || bb >= 2 * n || vs[aa][bb]) continue;
                if(grid[aa][bb]) {
                    dfs(aa,bb);
                }
            }
        }
        for(int i = 0; i < b.size(); i++){
            for(int k = 0; k < 4; k++){
                int aa = b[i].first + xx[k], bb = b[i].second + yy[k];
                if(aa < 0 || bb < 0 || aa >= 2 * n || bb >= 2 * n || vs[aa][bb]) continue;
                dfs(aa,bb);
            }
        }
    }
    cout << "YES" << endl;
    for(int i = n - 1; i >= 0; i--){
        cout << ans[i] + 1 << endl;
    }
    
    
    
    return 0;
}

Compilation message (stderr)

skyscrapers.cpp: In function 'bool check()':
skyscrapers.cpp:36:13: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |     while(j < b.size()){
      |           ~~^~~~~~~~~~
skyscrapers.cpp: In function 'int main()':
skyscrapers.cpp:105:26: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  105 |         for(int i = 1; i < nxt.size(); i++){
      |                        ~~^~~~~~~~~~~~
skyscrapers.cpp:109:17: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  109 |         while(j < b.size()){
      |               ~~^~~~~~~~~~
skyscrapers.cpp:121:26: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  121 |         for(int i = 0; i < b.size(); i++){
      |                        ~~^~~~~~~~~~
skyscrapers.cpp:130:26: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  130 |         for(int i = 0; i < b.size(); i++){
      |                        ~~^~~~~~~~~~

• 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