Submission #116016

#	Time	Username	Problem	Language	Result	Execution time	Memory
116016		Meloric	Triangles (CEOI18_tri)	C++14	0 / 100	3 ms	640 KiB

tri

#include <bits/stdc++.h>
#include "trilib.h"
#define pb push_back
#define X first
#define Y second
#define pii pair<int, int>

using namespace std;
bool ask(int a, int b, int c){
    a++; b++; c++;
    return is_clockwise(a, b, c);
}
bool cmp(int a, int b){
    if(a==b)return 0;
    return ask(0, a, b);
}
int main(){
    ios_base::sync_with_stdio(false);
    int n; n = get_n();
    if(n==3)give_answer(3);
    vector<int> up, dw, hull;
    dw.pb(1);
    for(int i = 2; i < n; i++){
        if(ask(0, 1, i))up.pb(i);
        else dw.pb(i);
    }
    sort(up.begin(), up.end(), cmp);
    sort(dw.begin(), dw.end(), cmp);
    dw.insert(dw.begin(), 0);

    for(int i = 0; i < dw.size(); i++){
        while(hull.size()>1 && ask(hull.end()[-2], hull.end()[-1], dw[i]))hull.pop_back();
        hull.pb(dw[i]);
    }
    for(int i = 0; i < up.size(); i++){
        while(hull.size()>1 && ask(hull.end()[-2], hull.end()[-1], up[i]))hull.pop_back();
        hull.pb(up[i]);
    }
    int sz = hull.size();
    for(int i = 0; i < dw.size(); i++){
        while(hull.size()>1 && ask(hull.end()[-2], hull.end()[-1], dw[i]))hull.pop_back();
        hull.pb(dw[i]);
    }
    for(int i = 0; i < up.size(); i++){
        while(hull.size()>1 && ask(hull.end()[-2], hull.end()[-1], up[i]))hull.pop_back();
        hull.pb(up[i]);
    }
    give_answer(hull.size()-sz);
    return 0;
}

Compilation message (stderr)

tri.cpp: In function 'int main()':
tri.cpp:31:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < dw.size(); i++){
                    ~~^~~~~~~~~~~
tri.cpp:35:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < up.size(); i++){
                    ~~^~~~~~~~~~~
tri.cpp:40:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < dw.size(); i++){
                    ~~^~~~~~~~~~~
tri.cpp:44:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < up.size(); i++){
                    ~~^~~~~~~~~~~

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