https://www.acgo.cn/application/1683033444409204736

https://www.acgo.cn/application/1683033444409204736

点击加入

我和“只因ikun团”的小伙伴都在ACGO等你，快用这个专属链接加入我们吧！https://www.acgo.cn/application/1682939046774235136

https://www.acgo.cn/problemset/2029/infohomeworkId=195&teamCode=1664181761155715072

#include<bits/stdc++.h> using namespace std; int main(){ int n; cin>>n; set<int>v; int ccin; for(int i=1;i<=n;i++){ cin>>ccin; v.insert(ccin); } cout<<v.size()<<endl; for(auto a:v){ cout<<a<<" "; } return 0; }