#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
using namespace std;
using mii = map<int, int>;
using vi = vector<int>;
using pii = pair<int, int>;
using vpii = vector<pii>;
#define sz(x) int(x.size())
const int dr = 0;
const int dt = 1;
const int dl = 2;
const int dd = 3;
const int INF = 2'000'000'001;
struct event
{
int t;
int i;
int j;
};
vpii delta{{+1, 0}, {0, +1}, {-1, 0}, {0, -1}};
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int N;
cin >> N;
int* X = new int[N];
int* Y = new int[N];
for(int i = 0; i < N; i++)
{
cin >> X[i] >> Y[i];
X[i] *= 2;
Y[i] *= 2;
}
int res = 1;
for(int i = N-1; i >= 0; i--)
{
X[i] -= X[0];
Y[i] -= Y[0];
}
for(int t = 0; t < 4; t++)
{
//cerr << "\n\n\n\n\n\n\n\n\n\n t = " << t << '\n';
vi dir(N);
dir[0] = dt;
for(int i = 1; i < N; i++)
{
//cerr << i << " <> " << X[i] << ' ' << Y[i] << " : " << int(Y[i] > 0) << ' ' << int(X[i]+Y[i]>0) << ' ' << int(Y[i]-X[i]>0) << '\n';
if(Y[i] > 0 && X[i]+Y[i] > 0 && Y[i]-X[i] > 0)
dir[i] = dd;
else if(Y[i] < 0 && X[i]+Y[i] <= 0 && Y[i]-X[i] <= 0)
dir[i] = dt;
else if(X[i] < 0)
dir[i] = dr;
else if(X[i] > 0)
dir[i] = dl;
//cerr << dir[i] << ' ' << dd << '\n';
}
//cerr << "\n\n\n";
for(int i = 0; i < N; i++) //cerr << X[i] << ' ' << Y[i] << ' ' << dir[i] << '\n';
vector<event> E;
for(int i = 0; i < N; i++)
{
for(int j = i+1; j < N; j++)
{
int t = -1;
if(X[i] == X[j])
t = abs(Y[j] - Y[i])/2;
else if(Y[i] == Y[j])
t = abs(X[j] - X[i])/2;
else
t = abs(X[i] - X[j]);
//cerr << "t = " << t << '\n';
pii di = delta[dir[i]];
pii dj = delta[dir[j]];
di.first *= t;
di.second *= t;
dj.first *= t;
dj.second *= t;
//cerr << di.first << ' ' << di.second << ' ' << dj.first << ' ' << dj.second << '\n';
//cerr << X[i] << ' ' << Y[i] << " " << X[j] << ' ' << Y[j] << '\n';
di.first += X[i];
di.second += Y[i];
dj.first += X[j];
dj.second += Y[j];
//cerr << di.first << ' ' << di.second << ' ' << dj.first << ' ' << dj.second << '\n';
if(di == dj && t != -1)
{
E.push_back({t, i, j});
}
}
}
//cerr << "events size = " << sz(E) << '\n';
vi infected(N, 0);
infected[0] = 1;
sort(E.begin(), E.end(), [] (event u, event v)
{
return u.t < v.t;
});
for(event e : E)
{
infected[e.i] = infected[e.j] = (infected[e.i] || infected[e.j]);
}
int curr = 0;
for(int i = 0; i < N; i++) curr += infected[i];
res = max(res, curr);
for(int i = 0; i < N; i++)
{
int newX = -Y[i], newY = X[i];
X[i] = newX;
Y[i] = newY;
}
}
cout << res << '\n';
}
Compilation message
fever.cpp: In function 'int main()':
fever.cpp:131:6: error: 'E' was not declared in this scope
131 | E.push_back({t, i, j});
| ^
fever.cpp:140:8: error: 'E' was not declared in this scope
140 | sort(E.begin(), E.end(), [] (event u, event v)
| ^