Submission #468144

#	Time	Username	Problem	Language	Result	Execution time	Memory
468144		ivan_tudor	Triangles (CEOI18_tri)	C++14	0 / 100	1 ms	292 KiB

tri

#include<bits/stdc++.h>
#include"trilib.h"
using namespace std;
int root;
bool cmp(int x, int y){
  return is_clockwise(root, x, y);
}
vector<int> getstv(vector<int> v, int st, int en){
  root = st;
  sort(v.begin(), v.end(), cmp);
  vector<int> stv;
  stv.push_back(st);
  for(auto x: v){
    while(stv.size() > 1 && is_clockwise(stv.end()[-2], stv.end()[-1], x) == false)
      stv.pop_back();
    stv.push_back(x);
  }
  return stv;
}
int main(){
  int n = get_n();
  int a = 1;
  int b = 2;
  vector<int> l, r;

  for(int i = 1; i<= n; i++){
    if(i == a)
      continue;
    if(i == b)
      continue;
    if(is_clockwise(a, b, i) == false)
      l.push_back(i);
    else
      r.push_back(i);
  }
 ///L ARE ORDINEA DE LA A LA B, R DE LA B LA A

  vector<int> stvl = getstv(l, a, b);
  vector<int> stvr = getstv(r, b, a);
  if(l.size() == 0){
    int x = a;
    while(stvr.size() > 1 && is_clockwise(stvr.end()[-2], stvr.end()[-1], x) == false)
      stvr.pop_back();
    stvr.push_back(x);
    give_answer(stvr.size());
    return 0 ;
  }
  if(r.size() == 0){
    int x = b;
    while(stvl.size() > 1 && is_clockwise(stvl.end()[-2], stvl.end()[-1], x) == false)
      stvl.pop_back();
    stvl.push_back(x);
    give_answer(stvl.size());
    return 0 ;
  }
  int fixed;
  if(stvl.size() < stvr.size())
    swap(stvl, stvr);
  vector<int> cstvl = stvl;
  for(auto x: stvr){
    while(cstvl.size() > 1 && (x == cstvl.end()[-1] || is_clockwise(cstvl.end()[-2], cstvl.end()[-1], x) == false))
      cstvl.pop_back();
  }
  fixed = cstvl.back();
  int poz = cstvl.size();
  vector<int> stv;
  stv.push_back(fixed);
  for(int i = poz; i < stvl.size(); i++){
    int x = stvl[i];
    while(stv.size() > 1 && (x == stv.end()[-1] || is_clockwise(stv.end()[-2], stv.end()[-1], x) == false))
      stv.pop_back();
    stv.push_back(x);
  }
  for(auto x: stvr){
    while(stv.size() > 1 && (x == stv.end()[-1] || is_clockwise(stv.end()[-2], stv.end()[-1], x) == false))
      stv.pop_back();
    stv.push_back(x);
  }
  for(int i = 0; i < poz - 1; i++){
    int x = stvl[i];
    while(stv.size() > 1 && (x == stv.end()[-1] || is_clockwise(stv.end()[-2], stv.end()[-1], x) == false))
      stv.pop_back();
    stv.push_back(x);
  }
  give_answer(stv.size());
}

Compilation message (stderr)

tri.cpp: In function 'int main()':
tri.cpp:68:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   68 |   for(int i = poz; i < stvl.size(); i++){
      |                    ~~^~~~~~~~~~~~~

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