#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
#define F first
#define S second
#define sz(x) int(x.size())
#define pb push_back
#define N 100005
#define M ll(998244353)
using namespace std;
//using namespace __gnu_pbds;
typedef long double ld;
typedef long long ll;
typedef short int si;
//typedef tree<int, null_type, less <int>, rb_tree_tag, tree_order_statistics_node_update> oredered_set;
int x[N], y[N], a[N][2], n, xr[N], yr[N];
set <int> tx[N * 4], ty[N * 4];
vector <int> pshx[N * 4], pshy[N * 4];
bool mk[N];
queue <pair <int, int> > qr;
queue <int> alone;
vector <pair <int, int> > vert, gorz;
void Push(int v, int tl, int tr)
{
while (sz(pshx[v]) > 0)
{
int val = pshx[v].back();
pshx[v].pop_back();
tx[v].insert(val);
if (tl != tr) {pshx[v + v].pb(val); pshx[v + v + 1].pb(val);}
}
while (sz(pshy[v]) > 0)
{
int val = pshy[v].back();
pshy[v].pop_back();
ty[v].insert(val);
if (tl != tr) {pshy[v + v].pb(val); pshy[v + v + 1].pb(val);}
}
}
void upd(int v, int tl, int tr, int l, int r, int val, bool f)
{
Push(v, tl, tr);
if (tl > tr || l > r || r < tl || tr < l) return;
if (l <= tl && tr <= r) {if (!f) pshx[v].pb(val); else pshy[v].pb(val); Push(v, tl, tr); return;}
int md = (tl + tr) >> 1;
upd(v + v, tl, md, l, r, val, f);
upd(v + v + 1, md + 1, tr, l, r, val, f);
}
bool good(int v, int tl, int tr, int pos, int l, int r, bool f)
{
Push(v, tl, tr);
if (tl == tr)
{
set <int> :: iterator it;
if (f)
{
it = ty[v].lower_bound(l);
return (it == ty[v].end() ? 1 : *it > r);
}
else
{
it = tx[v].lower_bound(l);
return (it == tx[v].end() ? 1 : *it > r);
}
}
else
{
int md = (tl + tr) >> 1;
if (pos <= md) return good(v + v, tl, md, pos, l, r, f);
return good(v + v + 1, md + 1, tr, pos, l, r, f);
}
}
bool gd(int fr, int sc)
{
if (x[fr] == x[sc])
{
if (y[fr] > y[sc]) swap(fr, sc);
return good(1, 1, N - 1, x[fr], y[fr], y[sc], 0);
}
else
{
if (x[fr] > x[sc]) swap(fr, sc);
return good(1, 1, N - 1, y[fr], x[fr], x[sc], 1);
}
}
void add(int fr, int sc)
{
if (x[fr] == x[sc])
{
gorz.pb({fr, sc});
if (y[fr] > y[sc]) swap(fr, sc);
upd(1, 1, N - 1, y[fr], y[sc], x[fr], 1);
}
else
{
vert.pb({fr, sc});
if (x[fr] > x[sc]) swap(fr, sc);
upd(1, 1, N - 1, x[fr], x[sc], y[fr], 0);
}
}
void clr(int x)
{
mk[x] = 1;
if (a[x][1] != -1) {if (!mk[a[x][1]]) alone.push(a[x][1]); a[x][1] = a[a[x][1]][1] = -1;}
if (a[x][0] != -1) {if (!mk[a[x][0]]) alone.push(a[x][0]); a[x][0] = a[a[x][0]][0] = -1;}
}
void fnd()
{
while (sz(alone) > 0)
{
int v = alone.front();
alone.pop();
if (a[i][1] != -1 && gd(i, a[i][1])) {qr.push({a[i][1], i}); a[i][1] = a[a[i][1]][1] = -1; return;}
if (a[i][0] != -1 && gd(i, a[i][0])) {qr.push({a[i][0], i}); a[i][0] = a[a[i][0]][0] = -1; return;}
cout << "NE" << endl;
exit(0);
}
for (int i = 0; i < n; i++)
{
if (mk[i]) continue;
if (a[i][1] == -1 && a[i][0] == -1) continue;
bool f0 = gd(i, a[i][0]);
bool f1 = gd(i, a[i][1]);
if (f0 && f1) continue;
if (!f0 && !f1) continue;
if (f0)
{
qr.push({i, a[i][0]});
a[i][0] = a[a[i][0]][0] = -1;
return;
}
else
{
qr.push({i, a[i][1]});
a[i][1] = a[a[i][1]][1] = -1;
return;
}
}
for (int i = 0; i < n; i++)
{
if (mk[i]) continue;
if (a[i][1] == -1 && a[i][0] == -1) continue;
if (!gd(i, a[i][0]) && !gd(i, a[i][1])) continue;
if (!gd(i, a[i][0]))
{
qr.push({i, a[i][1]});
a[i][1] = a[a[i][1]][1] = -1;
return;
}
else
{
qr.push({i, a[i][0]});
a[i][0] = a[a[i][0]][0] = -1;
return;
}
}
}
int main()
{
ios_base::sync_with_stdio(0); istream::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n;
for (int i = 1; i < N; i++) xr[i] = yr[i] = -1;
for (int i = 0; i < n; i++) {cin >> x[i] >> y[i]; a[i][0] = a[i][1] = -1;}
for (int i = 0; i < n; i++)
{
int X = x[i], Y = y[i];
if (xr[X] == -1) xr[X] = i; else {a[i][0] = xr[X]; a[xr[X]][0] = i;}
if (yr[Y] == -1) yr[Y] = i; else {a[i][1] = yr[Y]; a[yr[Y]][1] = i;}
}
for (int i = 0; i < n; i++) if (a[i][0] == a[i][1] && a[i][1] == -1) {cout << "NE" << endl; exit(0);}
for (int i = 0; i < n; i++) if (a[i][0] == -1 || a[i][1] == -1) alone.push(i);
fnd();
while (sz(qr) > 0)
{
int fr = qr.front().F;
int sc = qr.front().S;
qr.pop();
if (gd(fr, sc))
{
mk[sc] = 1;
clr(fr);
clr(sc);
add(fr, sc);
}
fnd();
}
if (sz(vert) + sz(gorz) != n / 2) {cout << "NE" << endl; exit(0);}
cout << "DA" << endl;
for (auto it : gorz) cout << it.F + 1 << " " << it.S + 1 << endl;
for (auto it : vert) cout << it.F + 1 << " " << it.S + 1 << endl;
}
Compilation message
matching.cpp: In function 'void fnd()':
matching.cpp:159:15: error: 'i' was not declared in this scope
if (a[i][1] != -1 && gd(i, a[i][1])) {qr.push({a[i][1], i}); a[i][1] = a[a[i][1]][1] = -1; return;}
^
matching.cpp:159:67: error: no matching function for call to 'std::queue<std::pair<int, int> >::push(<brace-enclosed initializer list>)'
if (a[i][1] != -1 && gd(i, a[i][1])) {qr.push({a[i][1], i}); a[i][1] = a[a[i][1]][1] = -1; return;}
^
In file included from /usr/include/c++/7/queue:64:0,
from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:86,
from matching.cpp:1:
/usr/include/c++/7/bits/stl_queue.h:251:7: note: candidate: void std::queue<_Tp, _Sequence>::push(const value_type&) [with _Tp = std::pair<int, int>; _Sequence = std::deque<std::pair<int, int>, std::allocator<std::pair<int, int> > >; std::queue<_Tp, _Sequence>::value_type = std::pair<int, int>]
push(const value_type& __x)
^~~~
/usr/include/c++/7/bits/stl_queue.h:251:7: note: no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'const value_type& {aka const std::pair<int, int>&}'
/usr/include/c++/7/bits/stl_queue.h:256:7: note: candidate: void std::queue<_Tp, _Sequence>::push(std::queue<_Tp, _Sequence>::value_type&&) [with _Tp = std::pair<int, int>; _Sequence = std::deque<std::pair<int, int>, std::allocator<std::pair<int, int> > >; std::queue<_Tp, _Sequence>::value_type = std::pair<int, int>]
push(value_type&& __x)
^~~~
/usr/include/c++/7/bits/stl_queue.h:256:7: note: no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'std::queue<std::pair<int, int> >::value_type&& {aka std::pair<int, int>&&}'
matching.cpp:161:15: error: 'i' was not declared in this scope
if (a[i][0] != -1 && gd(i, a[i][0])) {qr.push({a[i][0], i}); a[i][0] = a[a[i][0]][0] = -1; return;}
^
matching.cpp:161:67: error: no matching function for call to 'std::queue<std::pair<int, int> >::push(<brace-enclosed initializer list>)'
if (a[i][0] != -1 && gd(i, a[i][0])) {qr.push({a[i][0], i}); a[i][0] = a[a[i][0]][0] = -1; return;}
^
In file included from /usr/include/c++/7/queue:64:0,
from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:86,
from matching.cpp:1:
/usr/include/c++/7/bits/stl_queue.h:251:7: note: candidate: void std::queue<_Tp, _Sequence>::push(const value_type&) [with _Tp = std::pair<int, int>; _Sequence = std::deque<std::pair<int, int>, std::allocator<std::pair<int, int> > >; std::queue<_Tp, _Sequence>::value_type = std::pair<int, int>]
push(const value_type& __x)
^~~~
/usr/include/c++/7/bits/stl_queue.h:251:7: note: no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'const value_type& {aka const std::pair<int, int>&}'
/usr/include/c++/7/bits/stl_queue.h:256:7: note: candidate: void std::queue<_Tp, _Sequence>::push(std::queue<_Tp, _Sequence>::value_type&&) [with _Tp = std::pair<int, int>; _Sequence = std::deque<std::pair<int, int>, std::allocator<std::pair<int, int> > >; std::queue<_Tp, _Sequence>::value_type = std::pair<int, int>]
push(value_type&& __x)
^~~~
/usr/include/c++/7/bits/stl_queue.h:256:7: note: no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'std::queue<std::pair<int, int> >::value_type&& {aka std::pair<int, int>&&}'
matching.cpp:155:13: warning: unused variable 'v' [-Wunused-variable]
int v = alone.front();
^
