The SetStack Computer UVA - 12096

#include<iterator>
#include <iostream>
#include <string>
#include <stack>
#include<cctype>
#include <queue>
#include <algorithm>
#include <set>
#include <sstream>
#include<map>
#include<vector>
using namespace std;

typedef set<int> Set;//自定义集合类型
map<Set, int> IDcache;//映射为ID

vector<Set> Setcache;

int ID(Set x) {
	if (IDcache.count(x)) return IDcache[x];
	Setcache.push_back(x);
	return IDcache[x] = Setcache.size() - 1;
}

//设定两个宏
#define ALL(x) x.begin(),x.end()
#define INS(x) inserter(x,x.begin())

int main() {
	stack<int>s;
	int n;
	cin >> n;
	for (int i = 0; i < n; i++) {
		string op;
		cin >> op;
		if (op[0] == 'P') s.push(ID(Set()));
		else if (op[0] == 'D') s.push(s.top());
		else {
			Set x1 = Setcache[s.top()];
			s.pop();
			Set x2 = Setcache[s.top()];
			s.pop();
			Set x;
			if (op[0] == 'U') 
				set_union(ALL(x1),ALL(x2),INS(x));
			if (op[0] == 'I')
				set_intersection(ALL(x1), ALL(x2), INS(x));
			if (op[0] == 'A') {
				x = x2;
				x.insert(ID(x1));
			}
			s.push(ID(x));

		}
		cout << Setcache[s.top()].size() << endl;
	}
}