sjjo

1

#include<bits/stdc++.h>
using namespace std;
int main()
{
    ios::sync_with_stdio(0);
    int t,c=1;
    cin>>t;
    while(t--){
        set<int> s1;
        set<int> s2;
        set<int> s3;
        set<int> s4;
        int n,x;cin>>n;
        set<int>::iterator it;
        while(n--) { cin>>x; s1.insert(x); }
        cin>>n;
        while(n--) { cin>>x; s2.insert(x); }
        cout<<"Case #"<<c++<<":\n";
        set_intersection(s1.begin(), s1.end(), s2.begin(), s2.end(), inserter(s4, s4.begin()));
        for(it=s4.begin();it!=s4.end();it++){
            if(it==s4.begin()) cout<<*it; else cout<<" "<<*it;
        }cout<<endl;
        set_union(s1.begin(), s1.end(), s2.begin(), s2.end(),inserter(s3, s3.begin()));
        for(it=s3.begin();it!=s3.end();it++){
            if(it==s3.begin()) cout<<*it; else cout<<" "<<*it;
        }cout<<endl;s4.clear();
        set_difference(s3.begin(), s3.end(), s2.begin(), s2.end(), inserter(s4, s4.begin()));
        for(it=s4.begin();it!=s4.end();it++){
            if(it==s4.begin()) cout<<*it; else cout<<" "<<*it;
        }cout<<endl;s4.clear();
        set_difference(s3.begin(), s3.end(), s1.begin(), s1.end(), inserter(s4, s4.begin()));
        for(it=s4.begin();it!=s4.end();it++){
            if(it==s4.begin()) cout<<*it; else cout<<" "<<*it;
        }cout<<endl;s4.clear();
    }
    return 0;
}

http://blog.youkuaiyun.com/liuwhitesnow/article/details/6720863