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  1. // bai 34
  2. #include <iostream>
  3. #include <vector>
  4. #include <cmath>
  5. using namespace std;
  6.  
  7. int a[25], n, d = 0;
  8. vector<int> r, res;
  9.  
  10. // kiểm tra r có phải vector lồi ko
  11. bool check() {
  12.     if (r.size() <= 1)
  13.         return true;
  14.     int i = 1; 
  15.     while (r[i] < r[i - 1])
  16.         i++;
  17.     while (r[i] > r[i - 1] && i < r.size())
  18.         i++;
  19.     return i >= r.size();
  20. }
  21.  
  22. void visit(int i) {
  23.     if (!check())
  24.         return;
  25.     if (r.size() > d) {
  26.         d = r.size();
  27.         res.clear();
  28.         for (int j = 0; j < r.size(); j++)
  29.             res.push_back(r[j]);
  30.     }
  31.     if (i >= n)
  32.         return;
  33.     r.push_back(a[i]);
  34.     if (check())
  35.         visit(i + 1);
  36.  
  37.     r.pop_back();
  38.     visit(i + 1);
  39. }
  40.  
  41. int main() {
  42.     cin>> n;
  43.     for (int i = 0; i < n; i++) {
  44.         cin>> a[i];
  45.     }
  46.     visit(0);
  47.     cout<< d<< endl;
  48.     for (int i = 0; i < d; i++)
  49.         cout<< res[i]<< " ";
  50. }
Success #stdin #stdout 0.01s 5284KB
comments (?)
stdin
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10
1 3 4 5 4 3 2 1 7 10
stdout
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7
5 4 3 2 1 7 10
https://ideone.com/G0qDLn
language:
C++ (gcc 8.3)
created:
9 hours ago
visibility:
public

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