set交并补操作

并集 set_union()
交集set_intersection()
补 set_difference()

#include<iostream>
#include<set>
#include<vector>
#include<algorithm>
using namespace std;

int main()
{
    set<int> a,b;
    vector<int> c;
    int n,m;
    cin>>n>>m;
    while(n--)
    {
        int x;
        cin>>x;
        a.insert(x);
    }
    while(m--)
    {
        int x;
        cin>>x;
        b.insert(x);
    }
    //并集
    set_union(a.begin(),a.end(),b.begin(),b.end(),back_inserter(c));
    for(int t:c)cout<<t<<" ";
    cout<<endl;
    c.clear();
    //交集
    set_intersection(a.begin(),a.end(),b.begin(),b.end(),back_inserter(c));
    for(int t:c)cout<<t<<" ";
    cout<<endl;
    c.clear();
    //差集
    set_difference(a.begin(),a.end(),b.begin(),b.end(),back_inserter(c));
    for(int t:c)cout<<t<<" ";
    cout<<endl;
    c.clear();
    return 0;
}

演示结果