Submission #115918

#	Time	Username	Problem	Language	Result	Execution time	Memory
115918		Meloric	Triangles (CEOI18_tri)	C++14	0 / 100	2 ms	384 KiB

tri

#include "trilib.h"
#include <bits/stdc++.h>
//#define int int64_t
#define pb push_back
#define X first
#define Y second
#define pii pair<int, int>
 
using namespace std;
/*
int get_n(){
    int c; cin >> c;
    return c;
}
void give_answer(int a){
    cout << a;
}
bool is_clockwise(int a, int b, int c){
    cout << a << ' '<<b <<' '<<c<<endl;
    bool d; cin >> d;
    return d;
}
*/
bool ask(int a, int b, int c){
    a++; b++; c++;
    return is_clockwise(a, b, c);
}
void quick(int l, int r, vector<int>&srt){
    if(r-l<2)return;
    vector<int> sml, big;
    int piv = srt[l];
    for(int i = l+1; i<r; i++){
        int cur = srt[i];
        if(ask(srt[0], piv, cur))sml.pb(cur);
        else big.pb(cur);
    }
    int counter = l;
    for(int i = 0; i < sml.size(); i++){
        srt[l+i] = sml[i];
        counter++;
    }
    srt[counter] = piv;
    counter++;
    for(int i = 0; i < big.size(); i++){
        srt[i+counter]=big[i];
    }
    /*
    for(auto i : srt)cout << i+1 <<' ';
    cout << endl;
    */
    quick(l, counter-1, srt);
    quick(counter, r, srt);
}
signed main(){
    ios_base::sync_with_stdio(false);
    //cin.tie(0);
    int n; n = get_n();
    if(n==3)give_answer(3);
    //assert(false);
    vector<int> srt(n);
    iota(srt.begin(), srt.end(), 0);
    srand(41);
    random_shuffle(srt.begin(), srt.end());
    quick(1, n, srt);
    //for(auto i : srt)cout << i+1 <<' ';
    for(int i = 0; i< n; i++)srt.pb(srt[i]);
    vector<int> hull;
    /*
    for(auto i : srt)cout << i+1 <<' ';
    cout << endl;
    */
    for(int i = 0; i< srt.size(); i++){
        int sz = hull.size();
        while(sz>1 && ask(hull[sz-2], hull[sz-1], srt[i])){
            hull.pop_back();
            sz--;
        }
        hull.pb(srt[i]);
    }
    vector<int> tmp(n);
    for(auto i : hull)tmp[i]++;
    int ans = 0;
    for(auto i : tmp){
        if(i == 2)ans++;
    }
    give_answer(ans);
    return 0;
}

Compilation message (stderr)

tri.cpp: In function 'void quick(int, int, std::vector<int>&)':
tri.cpp:38:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < sml.size(); i++){
                    ~~^~~~~~~~~~~~
tri.cpp:44:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < big.size(); i++){
                    ~~^~~~~~~~~~~~
tri.cpp: In function 'int main()':
tri.cpp:72:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i< srt.size(); i++){
                    ~^~~~~~~~~~~~

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