题目：https://pintia.cn/problem-sets/994805260223102976/problems/994805266942377984

测试点3有点坑，要补全为0
最大值是100000

代码

  1. #include<cstdio>
  2. #include<algorithm>
  3. #include<map>
  4. #include<iostream>
  5. #include<set>
  6. using namespace std;
  8. map<int, int> mp;
  9. set<int> st;
  11. int main(){
  12.     int n, m;
  13.     int hash[100000] = {0};
  14.     int temp1, temp2;
  15.     scanf("%d", &n);
  16.     for(int i = 0 ; i < n; i++){
  17.         scanf("%d%d", &temp1, &temp2);
  18.         mp[temp1] = temp2;
  19.         mp[temp2] = temp1;
  20.     }
  21.     scanf("%d", &m);
  22.     for(int i = 0; i < m; i++){
  23.         scanf("%d", &temp1);
  24.         hash[temp1] = 1;
  25.         st.insert(temp1);
  26.     }
  27.     for(int i = 0; i < 100000; i++){
  28.         if(hash[i] == 1){
  29.             if(mp.find(i) != mp.end() && hash[mp[i]] == 1){
  30.                 st.erase(i);
  31.             }
  32.         }
  33.     }
  34.     cout<<st.size()<<endl;
  35.     int first = 0;
  36.     for(auto it = st.begin(); it != st.end(); it++){
  37.         if(first) cout<<" ";                
  38.         printf("%05d", *it);
  39.         first=1;
  40.     }
  41. }