11

Run ID	Author	Problem	Lang	Verdict	Time	Memory	Code Length	Submit Time
11	admin	[在线测评解答教程] 求和	C++	Accepted	1 MS	288 KB	141	2024-12-10 20:26:11

#include <iostream> using namespace std; int main() { int t, n; while (cin >> n) { cout << (n + 1)*n / 2<<endl; } return 0; }