## Editorial for Bắn máy bay

Remember to use this editorial only when stuck, and not to copy-paste code from it. Please be respectful to the problem author and editorialist.
Submitting an official solution before solving the problem yourself is a bannable offence.

Lưu ý: Các code mẫu dưới đây chỉ mang tính tham khảo và có thể không AC được bài tập này

#### Code mẫu của flashmt

#include <iostream>
using namespace std;

int isTriangle(int x1,int y1,int x2,int y2,int x3,int y3)
{
return 1LL*(x1-x2)*(y2-y3)!=1LL*(y2-y1)*(x3-x2);
}

int main()
{
int n,x[222],y[222],d[222]={0},total=0;
cin >> n;
for (int i=0;i<n;i++) cin >> x[i] >> y[i];
for (int i=0;i<n;i++)
for (int j=i+1;j<n;j++)
for (int k=j+1;k<n;k++)
if (isTriangle(x[i],y[i],x[j],y[j],x[k],y[k]))
d[i]++, d[j]++, d[k]++, total++;

int mn=1<<30,ans;
for (int i=0;i<n;i++)
if (d[i]<mn) mn=d[i], ans=i+1;
cout << total << ' ' << ans << endl;
}


#### Code mẫu của happyboy99x

#include<cstdio>
#include<climits>

#define N 200
long long x[N], y[N];
int safe[N], strongValue, n;

int main() {
scanf("%d", &n);
for(int i = 0; i < n; ++i) scanf("%lld%lld", x+i, y+i);
for(int i = 0; i < n; ++i)
for(int j = i+1; j < n; ++j)
for(int k = j+1; k < n; ++k)
if((x[j]-x[i])*(y[k]-y[j]) != (x[k]-x[j])*(y[j]-y[i])) {
++strongValue; ++safe[i]; ++safe[j]; ++safe[k];
}
int min = INT_MAX, pos;
for(int i = 0; i < n; ++i)
if(safe[i] < min) {
min = safe[i];
pos = i;
}
printf("%d %d\n", strongValue, pos+1);
return 0;
}


program c11trcnt;
uses    math;
type    point=record
x,y:longint;
s:longint;
end;

vector=record
x,y:int64;
end;
const   maxN=222;
fi='';
var     a:array[1..maxN] of point;
n,res:longint;

procedure input;
var     inp:text;
i:longint;
begin
assign(inp,fi);
reset(inp);
for i:=1 to n do
close(inp);
end;

procedure process;
var     i,j,k:longint;
v1,v2:vector;
begin
for i:=1 to n do
for j:=i+1 to n do
for k:=j+1 to n do
begin
v1.x:=a[j].x-a[i].x;
v1.y:=a[j].y-a[i].y;
v2.x:=a[k].x-a[i].x;
v2.y:=a[k].y-a[i].y;
if not ((v1.x*v2.y)=(v1.y*v2.x)) then
begin
inc(res);
inc(a[i].s);
inc(a[j].s);
inc(a[k].s);
end;
end;
end;

procedure output;
var     t,i:longint;
begin
write(res,' ');
t:=1;
for i:=2 to n do
if a[i].s<a[t].s then
t:=i;
write(t);

end;

begin
input;
process;
output;
end.


#### Code mẫu của RR

#include <sstream>
#include <iomanip>
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <string>
#include <deque>
#include <complex>

#define FOR(i,a,b) for(int i=(a),_b=(b); i<=_b; i++)
#define FORD(i,a,b) for(int i=(a),_b=(b); i>=_b; i--)
#define REP(i,a) for(int i=0,_a=(a); i<_a; i++)
#define FORN(i,a,b) for(int i=(a),_b=(b);i<_b;i++)
#define DOWN(i,a,b) for(int i=a,_b=(b);i>=_b;i--)
#define SET(a,v) memset(a,v,sizeof(a))
#define sqr(x) ((x)*(x))
#define ll long long
#define F first
#define S second
#define PB push_back
#define MP make_pair

#define DEBUG(x) cout << #x << " = "; cout << x << endl;
#define PR(a,n) cout << #a << " = "; FOR(_,1,n) cout << a[_] << ' '; cout << endl;
#define PR0(a,n) cout << #a << " = "; REP(_,n) cout << a[_] << ' '; cout << endl;
using namespace std;

int INP,AM,REACHEOF;
#define BUFSIZE (1<<12)
char BUF[BUFSIZE+1], *inp=BUF;
#define GETCHAR(INP) { \
if(!*inp) { \
if (REACHEOF) return 0;\
memset(BUF,0,sizeof BUF);\
if (inpzzz != BUFSIZE) REACHEOF = true;\
inp=BUF; \
} \
INP=*inp++; \
}
#define DIG(a) (((a)>='0')&&((a)<='9'))
#define GN(j) { \
AM=0;\
GETCHAR(INP); while(!DIG(INP) && INP!='-') GETCHAR(INP);\
if (INP=='-') {AM=1;GETCHAR(INP);} \
j=INP-'0'; GETCHAR(INP); \
while(DIG(INP)){j=10*j+(INP-'0');GETCHAR(INP);} \
if (AM) j=-j;\
}

const long double PI = acos((long double) -1.0);

struct Point {
int x, y;

Point(int x = 0, int y = 0) : x(x), y(y) {}

scanf("%d%d", &x, &y);
}

Point operator - (Point a) { return Point(x-a.x, y-a.y); }
} a[211];

int ccw(Point a, Point b, Point c) {
b = b - a;
c = c - a;
long long t = b.x*(ll)c.y - b.y*(ll)c.x;
if (t == 0) return 0;
else return 1;
}

int cnt[211], res;

int main() {
int n; scanf("%d", &n);

FOR(i,1,n) FOR(j,i+1,n) FOR(k,j+1,n)
if (ccw(a[i], a[j], a[k])) {
res++;
cnt[i]++;
cnt[j]++;
cnt[k]++;
}
printf("%d ", res);
int best = 1;
FOR(i,2,n) if (cnt[i] < cnt[best]) best = i;
printf("%d\n", best);
return 0;
}


#### Code mẫu của hieult

#include <set>
#include <map>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <string>
#include <vector>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <iomanip>
#include <iostream>
#include <algorithm>
#include <ctime>
#include <deque>
#include <bitset>
#include <cctype>
#include <utility>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef unsigned int ui;
typedef unsigned long long ull;

#define Rep(i,n) for(int i = 0; i < (n); ++i)
#define Repd(i,n) for(int i = (n)-1; i >= 0; --i)
#define For(i,a,b) for(int i = (a); i <= (b); ++i)
#define Ford(i,a,b) for(int i = (a); i >= (b); --i)
#define Fit(i,v) for(__typeof((v).begin()) i = (v).begin(); i != (v).end(); ++i)
#define Fitd(i,v) for(__typeof((v).rbegin()) i = (v).rbegin(); i != (v).rend(); ++i)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define sz(a) ((int)(a).size())
#define all(a) (a).begin(), (a).end()
#define ms(a,x) memset(a, x, sizeof(a))

template<class F, class T> T convert(F a, int p = -1) {
stringstream ss;
if (p >= 0)
ss << fixed << setprecision(p);
ss << a;
T r;
ss >> r;
return r;
}
template<class T> T gcd(T a, T b) {
T r;
while (b != 0) {
r = a % b;
a = b;
b = r;
}
return a;
}
template<class T> T lcm(T a, T b) {
return a / gcd(a, b) * b;
}
template<class T> T sqr(T x) {
return x * x;
}
template<class T> T cube(T x) {
return x * x * x;
}
template<class T> int getbit(T s, int i) {
return (s >> i) & 1;
}
template<class T> T onbit(T s, int i) {
return s | (T(1) << i);
}
template<class T> T offbit(T s, int i) {
return s & (~(T(1) << i));
}
template<class T> int cntbit(T s) {
return s == 0 ? 0 : cntbit(s >> 1) + (s & 1);
}

const int bfsz = 1 << 16;
char bf[bfsz + 5];
int rsz = 0;
int ptr = 0;
char gc() {
if (rsz <= 0) {
ptr = 0;
rsz = (int) fread(bf, 1, bfsz, stdin);
if (rsz <= 0)
return EOF;
}
--rsz;
return bf[ptr++];
}
void ga(char &c) {
c = EOF;
while (!isalpha(c))
c = gc();
}
int gs(char s[]) {
int l = 0;
char c = gc();
while (isspace(c))
c = gc();
while (c != EOF && !isspace(c)) {
s[l++] = c;
c = gc();
}
s[l] = '\0';
return l;
}
template<class T> bool gi(T &v) {
v = 0;
char c = gc();
while (c != EOF && c != '-' && !isdigit(c))
c = gc();
if (c == EOF)
return false;
bool neg = c == '-';
if (neg)
c = gc();
while (isdigit(c)) {
v = v * 10 + c - '0';
c = gc();
}
if (neg)
v = -v;
return true;
}

typedef pair<int, int> II;
const ld PI = acos(-1.0);
const ld eps = 1e-9;
const int dr[] = { -1, 0, +1, 0, 1, 1, -1, -1 };
const int dc[] = { 0, +1, 0, -1, 1, -1, 1, -1 };
const int inf = (int) 1e9 + 5;
const ll linf = (ll) 1e16 + 5;
const int mod = (ll) (1e4 + 7 + eps);
#define maxn 205

struct Point{
ll x, y;
Point(){};
Point(ll _x, ll _y){
x = _x; y = _y;
}
};

int ccw(Point P0, Point P1, Point P2){
ll dx1 = P1.x - P0.x, dy1 = P1.y - P0.y;
ll dx2 = P2.x - P0.x, dy2 = P2.y - P0.y;
ll d = dx1 * dy2 - dx2 * dy1;
if(d == 0) return 0;
return d < 0 ? -1 : 1;
}

Point A[maxn];
int n, f[maxn];

int main() {
//  freopen("in.txt", "r", stdin);

cin >> n;
For(i, 1, n) cin >> A[i].x >> A[i].y;
ms(f, 0);
int res = 0;
For(i, 1, n) For(j, i + 1, n) For(k, j + 1, n){
if(ccw(A[i], A[j], A[k]) != 0){
f[i]++;
f[j]++;
f[k]++;
res++;
}
}

int MAX = inf, chiso = -1;
For(i, 1, n) if(f[i] < MAX){
MAX = f[i];
chiso = i;
}

cout << res << " " << chiso << endl;

return 0;

}


#### Code mẫu của skyvn97

#include<stdio.h>
#define MAX   250
typedef long long ll;
struct pos
{
ll x,y;
};
pos a[MAX];
ll t[MAX];
int n,i,j,k,m,c;
int main(void)
{
scanf("%d",&n);
for (i=1;i<=n;i=i+1)
{
scanf("%d",&a[i].x);
scanf("%d",&a[i].y);
t[i]=0;
}
c=0;
for (i=1;i<n-1;i=i+1)
for (j=i+1;j<n;j=j+1)
for (k=j+1;k<=n;k=k+1)
if ((a[i].y-a[j].y)*(a[i].x-a[k].x)!=(a[i].y-a[k].y)*(a[i].x-a[j].x))
{
t[i]++;
t[j]++;
t[k]++;
c++;
}
m=t[1];
k=1;
for (i=2;i<=n;i=i+1)
if (t[i]<m)
{
m=t[i];
k=i;
}
printf("%d %d",c,k);
return 0;
}