1121. Damn Single (25)

这题挺水

#include<iostream>
#include<string>
#include<map>
#include<vector>
#include<algorithm>
#include<queue>
#include<set>
#include<stack>
using namespace std;
const int inf = 99999999;




int main() {
  map<int, int> couple;
  int num;
  cin >> num;
  for(int i = 0; i < num; i++) {
    int n1, n2;
    cin >> n1 >> n2;
    couple[n1] = n2;
    couple[n2] = n1;
  }

  int n;
  int c = 0;
  vector<int>arr;
  cin >> n;
  for (int i = 0; i < n; i++) {
    int k;
    cin >> k;
    arr.push_back(k);
  }
  vector<int> single;
  for (int i = 0; i < n; i++) {
    

    if (find(arr.begin(), arr.end(), couple[arr[i]]) == arr.end()) {
      c++;
      single.push_back(arr[i]);
    }
  }
  
  cout << c << endl;
  sort(single.begin(), single.end());
  for (int i = 0; i < single.size(); i++) {
    if (i == 0) {
      printf("%05d", single[i]);
    }
    else {
      printf(" %05d", single[i]);
    }
  }

  system("pause");
}