2231

Run ID	Author	Problem	Lang	Verdict	Time	Memory	Code Length	Submit Time
2231	Duck	[在线测评解答教程] 求和	C++	Accepted	0 MS	244 KB	154	2022-12-04 17:29:00

#include<bits/stdc++.h> using namespace std; int main() { int n; while (scanf("%d",&n) != EOF) printf("%d\n", (n + 1) * n / 2); return 0; }