#include <bits/stdc++.h>
using namespace std;
void dfs(int x, vector<vector<int>> &AR, vector<int> &occ, int &nb)
{
if (occ[x])
return;
nb--;
occ[x] = 1;
for (int i = 0; i < AR[x].size(); i++)
{
dfs(AR[x][i], AR, occ, nb);
}
}
class UnionFind
{
private:
vector<int> p;
public:
UnionFind(int x)
{
p.assign(x, 0);
for (int i = 0; i < x; i++)
p[i] = i;
}
int find(int x) { return (p[x] == x) ? x : p[x] = find(p[x]); }
void merge(int a, int b)
{
int x = find(a), y = find(b);
if (x == y)
return;
p[x] = y;
}
};
int main()
{
int N, T;
cin >> N >> T;
map<pair<int, int>, int> M;
vector<pair<int, int>> Tab;
vector<vector<int>> AR, AR2;
vector<pair<int, int>> trans1 = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}}, trans2 = {{-1, -1}, {-1, 0}, {-1, 1}, {0, -1}, {0, 1}, {1, -1}, {1, 0}, {1, 1}};
int buff = 0;
for (int i = 0; i < N; i++)
{
int x, y;
cin >> x >> y;
Tab.push_back({x, y});
M[{x, y}] = buff++;
AR.push_back({});
AR2.push_back({});
for (int j = 0; j < 4; j++)
if (M.count({x + trans1[j].first, y + trans1[j].second}))
{
AR[i].push_back(M[{x + trans1[j].first, y + trans1[j].second}]);
AR[M[{x + trans1[j].first, y + trans1[j].second}]].push_back(i);
}
for (int j = 0; j < 8; j++)
if (M.count({x + trans2[j].first, y + trans2[j].second}))
{
AR2[i].push_back(M[{x + trans2[j].first, y + trans2[j].second}]);
AR2[M[{x + trans2[j].first, y + trans2[j].second}]].push_back(i);
}
}
vector<int> ans, occ(N);
int nb = N;
dfs(0, AR2, occ, nb);
if (nb)
{
cout << "NO" << '\n';
return 0;
}
pair<int, int> minn = {1000000010, 0};
for (int i = 0; i < N; i++)
{
for (int j = 0; j < 8; j++)
{
int x = Tab[i].first + trans2[j].first, y = Tab[i].second + trans2[j].second;
if (M.count({x, y}) == 0)
{
M[{x, y}] = buff++;
minn = min(minn, {x, y});
Tab.push_back({x, y});
AR.push_back({});
AR2.push_back({});
for (int k = 0; k < 4; k++)
if (M.count({x + trans1[k].first, y + trans1[k].second}))
{
AR[buff - 1].push_back(M[{x + trans1[k].first, y + trans1[k].second}]);
AR[M[{x + trans1[k].first, y + trans1[k].second}]].push_back(buff - 1);
}
}
}
}
UnionFind UF(buff);
occ.assign(buff, 0);
occ[M[minn]] = 1;
queue<int> Q;
Q.push(M[minn]);
vector<int> done(N);
priority_queue<int> next;
for (int i = N; i < buff; i++)
{
for (int j = 0; j < AR[i].size(); j++)
{
if (AR[i][j] < N)
continue;
UF.merge(i, AR[i][j]);
}
}
while (!Q.empty())
{
int x = Q.front();
Q.pop();
for (int i = 0; i < AR[x].size(); i++)
{
if (occ[AR[x][i]])
continue;
occ[AR[x][i]] = 1;
if (AR[x][i] >= N)
Q.push(AR[x][i]);
else
next.push(AR[x][i]);
}
}
while (!next.empty())
{
int x = next.top();
next.pop();
if (done[x])
continue;
vector<int> count = {M[{Tab[x].first - 1, Tab[x].second - 1}], M[{Tab[x].first - 1, Tab[x].second}], M[{Tab[x].first - 1, Tab[x].second + 1}], M[{Tab[x].first, Tab[x].second + 1}], M[{Tab[x].first + 1, Tab[x].second + 1}], M[{Tab[x].first + 1, Tab[x].second}], M[{Tab[x].first + 1, Tab[x].second - 1}], M[{Tab[x].first, Tab[x].second - 1}]};
for (int i = 0; i < 8; i++)
count[i] = ((count[i] >= N || done[count[i]]) ? 0 : 1);
int u = M[{Tab[x].first - 1, Tab[x].second}], d = M[{Tab[x].first + 1, Tab[x].second}], l = M[{Tab[x].first, Tab[x].second - 1}], r = M[{Tab[x].first, Tab[x].second + 1}];
if ((u >= N || done[u]) && (d >= N || done[d]) && UF.find(u) == UF.find(d))
{
if (count[0] + count[6] + count[7] && count[2] + count[3] + count[4])
continue;
}
if ((l >= N || done[l]) && (r >= N || done[r]) && UF.find(l) == UF.find(r))
{
if (count[0] + count[1] + count[2] && count[4] + count[5] + count[6])
continue;
}
if ((u >= N || done[u]) && (l >= N || done[l]) && UF.find(u) == UF.find(l))
{
if (count[0] && count[2] + count[3] + count[4] + count[5] + count[6])
continue;
}
if ((u >= N || done[u]) && (r >= N || done[r]) && UF.find(u) == UF.find(r))
{
if (count[0] + +count[4] + count[5] + count[6] + count[7] && count[2])
continue;
}
if ((l >= N || done[l]) && (d >= N || done[d]) && UF.find(l) == UF.find(d))
{
if (count[0] + count[1] + count[2] + count[3] + count[4] && count[6])
continue;
}
if ((r >= N || done[r]) && (d >= N || done[d]) && UF.find(r) == UF.find(d))
{
if (count[0] + count[6] + count[7] + count[1] + count[2] && count[4])
continue;
}
ans.push_back(x);
done[x] = 1;
for (int i = 0; i < AR[x].size(); i++)
{
if (AR[x][i] >= N || done[AR[x][i]])
UF.merge(i, AR[x][i]);
}
Q.push(x);
while (!Q.empty())
{
int y = Q.front();
Q.pop();
for (int i = 0; i < AR[y].size(); i++)
{
if (occ[AR[y][i]])
continue;
occ[AR[y][i]] = 1;
if (AR[y][i] >= N)
Q.push(AR[y][i]);
else
next.push(AR[y][i]);
}
}
for (int i = 0; i < AR2[x].size(); i++)
{
if (AR2[x][i] >= N || done[AR2[x][i]] || occ[AR2[x][i]] == 0)
continue;
next.push(AR2[x][i]);
}
}
cout << "YES" << '\n';
for (int i = N - 1; i >= 0; i--)
{
cout << ans[i] + 1 << '\n';
}
}
Compilation message
skyscrapers.cpp: In function 'void dfs(int, std::vector<std::vector<int> >&, std::vector<int>&, int&)':
skyscrapers.cpp:9:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
9 | for (int i = 0; i < AR[x].size(); i++)
| ~~^~~~~~~~~~~~~~
skyscrapers.cpp: In function 'int main()':
skyscrapers.cpp:104:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
104 | for (int j = 0; j < AR[i].size(); j++)
| ~~^~~~~~~~~~~~~~
skyscrapers.cpp:115:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
115 | for (int i = 0; i < AR[x].size(); i++)
| ~~^~~~~~~~~~~~~~
skyscrapers.cpp:169:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
169 | for (int i = 0; i < AR[x].size(); i++)
| ~~^~~~~~~~~~~~~~
skyscrapers.cpp:179:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
179 | for (int i = 0; i < AR[y].size(); i++)
| ~~^~~~~~~~~~~~~~
skyscrapers.cpp:190:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
190 | for (int i = 0; i < AR2[x].size(); i++)
| ~~^~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
348 KB |
ans=YES N=1 |
| 2 |
Correct |
0 ms |
348 KB |
ans=YES N=4 |
| 3 |
Correct |
1 ms |
348 KB |
ans=NO N=4 |
| 4 |
Correct |
0 ms |
344 KB |
ans=YES N=5 |
| 5 |
Correct |
1 ms |
348 KB |
ans=YES N=9 |
| 6 |
Correct |
0 ms |
348 KB |
ans=YES N=5 |
| 7 |
Correct |
0 ms |
432 KB |
ans=NO N=9 |
| 8 |
Correct |
1 ms |
348 KB |
ans=NO N=10 |
| 9 |
Incorrect |
1 ms |
344 KB |
Full cells must be connected |
| 10 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
348 KB |
ans=YES N=1 |
| 2 |
Correct |
0 ms |
348 KB |
ans=YES N=4 |
| 3 |
Correct |
1 ms |
348 KB |
ans=NO N=4 |
| 4 |
Correct |
0 ms |
344 KB |
ans=YES N=5 |
| 5 |
Correct |
1 ms |
348 KB |
ans=YES N=9 |
| 6 |
Correct |
0 ms |
348 KB |
ans=YES N=5 |
| 7 |
Correct |
0 ms |
432 KB |
ans=NO N=9 |
| 8 |
Correct |
1 ms |
348 KB |
ans=NO N=10 |
| 9 |
Incorrect |
1 ms |
344 KB |
Full cells must be connected |
| 10 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
348 KB |
ans=YES N=1 |
| 2 |
Correct |
0 ms |
348 KB |
ans=YES N=4 |
| 3 |
Correct |
1 ms |
348 KB |
ans=NO N=4 |
| 4 |
Correct |
0 ms |
344 KB |
ans=YES N=5 |
| 5 |
Correct |
1 ms |
348 KB |
ans=YES N=9 |
| 6 |
Correct |
0 ms |
348 KB |
ans=YES N=5 |
| 7 |
Correct |
0 ms |
432 KB |
ans=NO N=9 |
| 8 |
Correct |
1 ms |
348 KB |
ans=NO N=10 |
| 9 |
Incorrect |
1 ms |
344 KB |
Full cells must be connected |
| 10 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
3 ms |
532 KB |
ans=NO N=1934 |
| 2 |
Correct |
4 ms |
604 KB |
ans=NO N=1965 |
| 3 |
Incorrect |
9 ms |
860 KB |
Full cells must be connected |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
348 KB |
ans=YES N=1 |
| 2 |
Correct |
0 ms |
348 KB |
ans=YES N=4 |
| 3 |
Correct |
1 ms |
348 KB |
ans=NO N=4 |
| 4 |
Correct |
0 ms |
344 KB |
ans=YES N=5 |
| 5 |
Correct |
1 ms |
348 KB |
ans=YES N=9 |
| 6 |
Correct |
0 ms |
348 KB |
ans=YES N=5 |
| 7 |
Correct |
0 ms |
432 KB |
ans=NO N=9 |
| 8 |
Correct |
1 ms |
348 KB |
ans=NO N=10 |
| 9 |
Incorrect |
1 ms |
344 KB |
Full cells must be connected |
| 10 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
203 ms |
14680 KB |
ans=NO N=66151 |
| 2 |
Correct |
124 ms |
10080 KB |
ans=NO N=64333 |
| 3 |
Incorrect |
536 ms |
19140 KB |
Full cells must be connected |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
3 ms |
532 KB |
ans=NO N=1934 |
| 2 |
Correct |
4 ms |
604 KB |
ans=NO N=1965 |
| 3 |
Incorrect |
9 ms |
860 KB |
Full cells must be connected |
| 4 |
Halted |
0 ms |
0 KB |
- |
