【数据结构1-3】集合—set

 1 #include<iostream>
 2 #include<set>
 3 using namespace std;
 4 int main()
 5 {
 6     set<int> s;
 7     int n;
 8     cin >> n;
 9     for (int i = 0; i < n; i++)
10     {
11         int tmp1, tmp2;
12         cin >> tmp1 >> tmp2;
13         if (tmp1 == 1)
14         {
15             if (s.find(tmp2) != s.end())
16                 cout << "Already Exist" << endl;
17             else
18                 s.insert(tmp2);
19         }
20         if (tmp1 == 2)
21         {
22             if (s.empty())
23                 cout << "Empty" << endl;
24             else
25             {
26                 auto it1 = s.lower_bound(tmp2);
27                 auto it2 = it1;
28                 if (it2 != s.begin())
29                     it2--;
30                 if (it1!=s.end()&&(tmp2 - *it2) > (*it1 - tmp2))
31                     it2 = it1;
32                 cout << *it2 << endl;
33                 s.erase(it2);
34             }
35         }
36     }
37     return 0;
38 }