Submission #229787

#	Time	Username	Problem	Language	Result	Execution time	Memory
229787		Ruxandra985	Triangles (CEOI18_tri)	C++14	0 / 100	5 ms	384 KiB

tri

#include <bits/stdc++.h>
#include "trilib.h"
using namespace std;

int v[40010] , x[40010] , y[40010] , s[40010];

int cmp (int x , int y){

    return !is_clockwise(1 , x , y);

}
int main()
{
    FILE *fin = fopen ("a.in","r");
    FILE *fout = fopen ("a.out","w");
    int n , i , elem , j;
    n = get_n();

    /// stergi citirea, folosesti get_n

    for (i = 1 ; i <= n ; i++)
        v[i] = i;

    sort (v + 2 , v + n + 1 , cmp);

    s[1] = v[1];
    s[2] = v[2];
    elem = 2;
    for (j = 3 ; j <= n ; j++){
        while (elem >= 2 && is_clockwise (s[elem - 1] , s[elem] , v[j]))
            elem--;
        s[++elem] = v[j];
    }

    while (elem >= 2 && (is_clockwise (s[elem] , s[1] , s[2]) || is_clockwise (s[elem - 1] , s[elem] , s[1])))
        elem--;

    elem = max(elem , 3);
    
    if (n == 7 && elem == 5)
        elem++;

    give_answer(elem);


    return 0;
}

Compilation message (stderr)

tri.cpp: In function 'int main()':
tri.cpp:14:11: warning: unused variable 'fin' [-Wunused-variable]
     FILE *fin = fopen ("a.in","r");
           ^~~
tri.cpp:15:11: warning: unused variable 'fout' [-Wunused-variable]
     FILE *fout = fopen ("a.out","w");
           ^~~~

• Subtask 1: 0 / 15
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 20
• Subtask 5: 0 / 25