1 #include "iostream"
 2 #include "vector"
 3 #include "set"
 4 #include "map"
 5 #include "stack"
 6 #include "string"
 7 #include "algorithm"
 8 #include "iterator"
 9 using namespace std;
10 #define ALL(x) x.begin(),x.end()//宏
11 #define INS(x) inserter(x,x.begin())//宏
12 typedef set <int> Set;
 
13 map<Set, int> IDcache;//集合映射成ID
14 vector<Set> Setcache;//根據ID取集合
15 int ID(Set x)//查找集合x的ID，找不到分配新的
16 {
17     if (IDcache.count(x))
18         return IDcache[x];
19     Setcache.push_back(x);//添加新集合
20     return IDcache[x] = Setcache.size() - 1;
21 }
22 int main()
23 {
24     stack<int> s;
 
25     int m;
26     cin >> m;
27     while (m--)
28     {
29         int n;
30         cin >> n;
31         for (int i = 0; i < n; i++)
32         {
33             string op;
34             cin >> op;
35             if (op[0] == ‘P‘)//PUSH
36                 s.push(ID(Set()));//空集入棧
37
 
             else
38                 if (op[0] == ‘D‘)//DUP,棧頂復制一次再入棧
39                     s.push(s.top());
40                 else
41                 {
42                     Set x1 = Setcache[s.top()];
43                     s.pop();
44                     Set x2 = Setcache[s.top()];
45                     s.pop();//出棧兩個集合
46                     Set x;
47                     if (op[0] == ‘U‘)//出棧兩個集合，並集入棧
48                         set_union(ALL(x1), ALL(x2), INS(x));
49                     //獲得兩個集合的並集。兩個輸入序列須保證已排好序
50                     if (op[0] == ‘I‘)//出棧兩個集合，交集入棧
51                         set_intersection(ALL(x1), ALL(x2), INS(x));
52                     if (op[0] == ‘A‘)//出棧兩個集合，先出棧的集合加到
53                     {    //後出棧的集合中，再入棧
54                         x = x2;
55                         x.insert(ID(x1));
56                     }
57                     s.push(ID(x));
58                 }
59             cout << Setcache[s.top()].size() << endl;
60         }
61         //if (m != 0)
62             cout << "***" << endl;
63     }
64     return 0;
65 }

UVA 12096 The SetStack Computer