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Run ID	Author	Problem	Lang	Verdict	Time	Memory	Code Length	Submit Time
10	admin	[在线测评解答教程] 求和	C++	Wrong Answer	0 MS	272 KB	109	2024-12-10 20:23:47

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