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;
}

Code mẫu của ladpro98

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);
        readln(inp,n);
        for i:=1 to n do
        readln(inp,a[i].x,a[i].y);
        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;

//Buffer reading
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);\
        int inpzzz = fread(BUF,1,BUFSIZE,stdin);\
        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;\
}
//End of buffer reading

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) {}

    void read() {
        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) a[i].read();

    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;
}