#include<bits/stdc++.h> using namespace std; set<int> s; int a[105]; int main(){ int n; cin>>n; for(int i=0;i<n;++i){ cin>>a[i]; s.insert(a[i]); } cout<<s.size()<<endl; while(!s.empty()){ cout<<*s.begin()<<" "; s.erase(s.begin()); } return 0; }
原文：https://www.cnblogs.com/JasonPeng1/p/11922444.html