Submission #1039223

#	Time	Username	Problem	Language	Result	Execution time	Memory
1039223		0npata	Triangles (CEOI18_tri)	C++17	55 / 100	1280 ms	980 KiB

tri

#include<bits/stdc++.h>
#include "trilib.h"

using namespace std;

int n;

bool is_clockw(int i, int j, int k) {
    return is_clockwise(i+1, j+1, k+1);
}

bool is_on_convex_hull(int i) {
    int mx = i == 0 ? 1 : 0;

    for(int j = 0; j<n; j++) {
        if(j == i || j == mx) continue;
        if(is_clockw(i, mx, j)) mx = j;
    }

    for(int j = 0; j<n; j++) {
        if(j == i || j == mx) continue;
        if(is_clockw(i, mx, j)) return false;
    }

    return true;
}

int32_t main() {
    n = get_n();
    
    int ans = 0;
    for(int i = 0; i<n; i++) {
        ans += is_on_convex_hull(i);
    }

    give_answer(ans);
    return 0;
}

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