78228

Run ID	Author	Problem	Lang	Verdict	Time	Memory	Code Length	Submit Time
78228	sh25_zhangjiajia	[在线测评解答教程] 求和	C++	Accepted	1 MS	240 KB	143	2025-12-26 15:29:53

#include<bits/stdc++.h> using namespace std; int main(){ int n; while(cin>>n){ cout<<n*(n+1)/2<<endl; } return 0; }