Submission #585081

#	Time	Username	Problem	Language	Result	Execution time	Memory
585081		Jomnoi	Triangles (CEOI18_tri)	C++17	0 / 100	1 ms	224 KiB

tri

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

bool ask(int a, int b, int c) {
    return is_clockwise(a, b, c);
}

int main() {
    int N = get_n();

    vector <int> cand, hull;
    for(int i = 1; i <= N; i++) {
        cand.push_back(i);
    }

    sort(cand.begin() + 1, cand.end(), [&](const int &a, const int &b) {
        return ask(1, a, b) == false;
    });

    for(auto p : cand) {
        while(hull.size() >= 2 and ask(hull[hull.size() - 2], hull.back(), p) == true) {
            hull.pop_back();
        }
        hull.push_back(p);
    }

    cand.pop_back();
    reverse(cand.begin(), cand.end());

    int len = hull.size();
    for(auto p : cand) {
        while(hull.size() > len and ask(hull[hull.size() - 2], hull.back(), p) == true) {
            hull.pop_back();
        }
        hull.push_back(p);
    }
    hull.pop_back();

    give_answer(hull.size());
    return 0;
}

Compilation message (stderr)

tri.cpp: In function 'int main()':
tri.cpp:33:27: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   33 |         while(hull.size() > len and ask(hull[hull.size() - 2], hull.back(), p) == true) {
      |               ~~~~~~~~~~~~^~~~~

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