UVA 12096 The SetStack Computer

<pre name="code" class="cpp">集合中不能有相同元素

set_union，<span style="font-family: Arial, Helvetica, sans-serif;">set_intersection 函数用前就应该保证输入两容器内有序且无重复</span>

<pre name="code" class="cpp">

#include <iostream>
#include <string>
#include <map>
#include <stack>
#include <vector>
#include <set>
#include <algorithm>
#include <cstdio>
#define ALL(x) x.begin(),x.end()
#define INS(x) inserter(x,x.begin())
using namespace std;
typedef set<int> Set;
vector<Set> Setcache;
map<Set,int> IDcache;
int ID(Set x);
int main()
{int n;cin>>n;while(n--){int k;cin>>k;stack<int> s;for(int i=0;i<k;i++){string c;cin>>c;if(c[0]=='P') s.push(ID(Set()));  //Set() ：新建一<span style="font-family: Arial, Helvetica, sans-serif;">空集合</span>else if(c[0]=='D') s.push(s.top());else{Set x1=Setcache[s.top()];s.pop();Set x2=Setcache[s.top()];s.pop();Set  x;if(c[0]=='U') set_union(ALL(x1),ALL(x2),INS(x));  if(c[0]=='I') set_intersection(ALL(x1),ALL(x2),INS(x));if(c[0]=='A') x=x2,x.insert(ID(x1));s.push(ID(x));}cout<<Setcache[s.top()].size()<<endl;}cout<<"***"<<endl;}
}
int ID(Set x)   
{           if(IDcache.count(x)) return IDcache[x];Setcache.push_back(x);return IDcache[x]=Setcache.size()-1;
}