Submission #120373

#	TimeUTC-0	Username	Problem	Language	Result	Execution time	Memory
120373	2019-06-24 09:23:43	tmwilliamlin168	Printed Circuit Board (CEOI12_circuit)	C++14	100 / 100	45 ms	4724 KiB

circuit

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#include <bits/stdc++.h>
using namespace std;
const int mxN=2e5;
int n, l, r;
long long x[mxN+1], y[mxN+1];
vector<int> v, s;
bool b[mxN];
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  
  auto cp=[](int a, int b, int c) {
    return (y[c]-y[a])*(x[b]-x[a])-(y[b]-y[a])*(x[c]-x[a]);
  };
  cin >> n;
  for(int i=0; i<n; ++i) {
    cin >> x[i] >> y[i];
    if(!i||cp(n, l, i)>0||!cp(n, l, i)&&x[i]<x[l])
      l=i;
    if(!i||cp(n, r, i)<0||!cp(n, r, i)&&x[i]<x[r])
      r=i;
  }
  int ic=cp((l+n-1)%n, l, (l+1)%n)>0?1:n-1;
  for(; l^r; l=(l+ic)%n)
    v.push_back(l);
  v.push_back(r);
  s={0, 1};
  for(int i=2; i<v.size(); ++i) {
 
 
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Compilation message (stderr)

circuit.cpp: In function 'int main()':
circuit.cpp:20:37: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   if(!i||cp(n, l, i)>0||!cp(n, l, i)&&x[i]<x[l])
                         ~~~~~~~~~~~~^~~~~~~~~~~
circuit.cpp:22:37: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   if(!i||cp(n, r, i)<0||!cp(n, r, i)&&x[i]<x[r])
                         ~~~~~~~~~~~~^~~~~~~~~~~
circuit.cpp:30:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=2; i<v.size(); ++i) {
               ~^~~~~~~~~

• Subtask 1: 100 / 100