#include <bits/stdc++.h>
#define sz(x) ((int)x.size())
#define pii pair<int,int>
#define ft first
#define sd second
#define all(x) x.begin(),x.end()
#define PB push_back
#define MP make_pair
using namespace std;
typedef long long ll;
const int md = int(1e9) + 7;
const int N = 2010;
const int PW = 20;
set<pii> st;
vector<pii> res;
vector<int> vc, vx[N], vy[N];
int n, x[N], y[N], sosed_x[N], sosed_y[N], kol[N];
bool mrk[N];
void BAD(){
cout << "NE";
exit(0);
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
// freopen("in.txt","r",stdin);
cin >> n;
vc.clear();
for (int i = 0; i < n; i++) {
cin >> x[i] >> y[i];
vc.PB(x[i]);
sosed_x[i] = sosed_y[i] = -1;
}
sort(all(vc));
vc.resize(unique(all(vc)) - vc.begin());
for (int i = 0; i < n; i++)
x[i] = lower_bound(all(vc), x[i]) - vc.begin();
vc.clear();
for (int i = 0; i < n; i++)
vc.PB(y[i]);
sort(all(vc));
vc.resize(unique(all(vc)) - vc.begin());
for (int i = 0; i < n; i++)
y[i] = lower_bound(all(vc), y[i]) - vc.begin();
for (int i = 0; i < n; i++){
vx[x[i]].PB(i);
vy[y[i]].PB(i);
}
for (int i = 0; i < n; i++){
if (sz(vx[i]) == 2){
sosed_x[vx[i][0]] = vx[i][1];
sosed_x[vx[i][1]] = vx[i][0];
kol[vx[i][0]]++;
kol[vx[i][1]]++;
}
if (sz(vy[i]) == 2){
sosed_y[vy[i][0]] = vy[i][1];
sosed_y[vy[i][1]] = vy[i][0];
kol[vy[i][0]]++;
kol[vy[i][1]]++;
}
}
for (int i = 0; i < n; i++)
st.insert(MP(kol[i], i));
while (sz(st)){
int v = (*st.begin()).sd;
st.erase(st.begin());
mrk[v] = 1;
if (kol[v] == 0)
BAD();
if (kol[v] == 2){
for (int i = 0; i < n; i++)
if (!mrk[i]){
mrk[i] = 1;
mrk[sosed_x[i]] = 1;
res.PB(MP(i, sosed_x[i]));
}
break;
}
if (sosed_x[v] >= 0){
int u = sosed_x[v];
mrk[u] = 1;
res.PB(MP(u, v));
st.erase(MP(kol[u], u));
int bd = max(y[u], y[v]);
for (int lf = min(y[v], y[u]); lf <= bd; lf++)
if (sz(vy[lf]) == 2){
int n1 = vy[lf][0], n2 = vy[lf][1];
if (min(x[n1], x[n2]) < x[v] && max(x[n1], x[n2]) > x[v]){
st.erase(MP(kol[n1], n1));
st.erase(MP(kol[n2], n2));
kol[n1]--;
kol[n2]--;
st.insert(MP(kol[n1], n1));
st.insert(MP(kol[n2], n2));
vy[lf].clear();
sosed_y[n1] = -1;
sosed_y[n2] = -1;
}
}
} else {
int u = sosed_y[v];
mrk[u] = 1;
res.PB(MP(u, v));
st.erase(MP(kol[u], u));
int bd = max(x[u], x[v]);
for (int lf = min(x[v], x[u]); lf <= bd; lf++)
if (sz(vx[lf]) == 2){
int n1 = vx[lf][0], n2 = vx[lf][1];
if (min(y[n1], y[n2]) < y[v] && max(y[n1], y[n2]) > y[v]){
st.erase(MP(kol[n1], n1));
st.erase(MP(kol[n2], n2));
kol[n1]--;
kol[n2]--;
st.insert(MP(kol[n1], n1));
st.insert(MP(kol[n2], n2));
vx[lf].clear();
sosed_x[n1] = -1;
sosed_x[n2] = -1;
}
}
}
}
cout << "DA\n";
for (pii cr : res)
cout << cr.ft + 1 << " " << cr.sd + 1 << '\n';
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
5 ms |
512 KB |
Output is correct |
2 |
Correct |
5 ms |
384 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
5 ms |
512 KB |
Output is correct |
2 |
Correct |
5 ms |
384 KB |
Output is correct |
3 |
Correct |
5 ms |
512 KB |
Output is correct |
4 |
Correct |
5 ms |
512 KB |
Output is correct |
5 |
Correct |
5 ms |
512 KB |
Output is correct |
6 |
Correct |
5 ms |
512 KB |
Output is correct |
7 |
Correct |
4 ms |
512 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
5 ms |
512 KB |
Output is correct |
2 |
Correct |
5 ms |
384 KB |
Output is correct |
3 |
Correct |
5 ms |
512 KB |
Output is correct |
4 |
Correct |
5 ms |
512 KB |
Output is correct |
5 |
Correct |
5 ms |
512 KB |
Output is correct |
6 |
Correct |
5 ms |
512 KB |
Output is correct |
7 |
Correct |
4 ms |
512 KB |
Output is correct |
8 |
Correct |
5 ms |
512 KB |
Output is correct |
9 |
Correct |
5 ms |
512 KB |
Output is correct |
10 |
Correct |
4 ms |
512 KB |
Output is correct |
11 |
Correct |
5 ms |
512 KB |
Output is correct |
12 |
Correct |
4 ms |
384 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
5 ms |
512 KB |
Output is correct |
2 |
Correct |
5 ms |
384 KB |
Output is correct |
3 |
Correct |
5 ms |
512 KB |
Output is correct |
4 |
Correct |
5 ms |
512 KB |
Output is correct |
5 |
Correct |
5 ms |
512 KB |
Output is correct |
6 |
Correct |
5 ms |
512 KB |
Output is correct |
7 |
Correct |
4 ms |
512 KB |
Output is correct |
8 |
Correct |
5 ms |
512 KB |
Output is correct |
9 |
Correct |
5 ms |
512 KB |
Output is correct |
10 |
Correct |
4 ms |
512 KB |
Output is correct |
11 |
Correct |
5 ms |
512 KB |
Output is correct |
12 |
Correct |
4 ms |
384 KB |
Output is correct |
13 |
Incorrect |
7 ms |
768 KB |
Output isn't correct |
14 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
5 ms |
512 KB |
Output is correct |
2 |
Correct |
5 ms |
384 KB |
Output is correct |
3 |
Correct |
5 ms |
512 KB |
Output is correct |
4 |
Correct |
5 ms |
512 KB |
Output is correct |
5 |
Correct |
5 ms |
512 KB |
Output is correct |
6 |
Correct |
5 ms |
512 KB |
Output is correct |
7 |
Correct |
4 ms |
512 KB |
Output is correct |
8 |
Correct |
5 ms |
512 KB |
Output is correct |
9 |
Correct |
5 ms |
512 KB |
Output is correct |
10 |
Correct |
4 ms |
512 KB |
Output is correct |
11 |
Correct |
5 ms |
512 KB |
Output is correct |
12 |
Correct |
4 ms |
384 KB |
Output is correct |
13 |
Incorrect |
7 ms |
768 KB |
Output isn't correct |
14 |
Halted |
0 ms |
0 KB |
- |