http://oj.acm./JudgeOnline/problem.php?id=4436
题解：等差数列
/**@Author: STZG*@Language: C++*/#include <bits/stdc++.h>#include<iostream>#include<algorithm>#include<cstdlib>#include<cstring>#include<cstdio>#include<string>#include<vector>#include<bitset>#include<queue>#include<deque>#include<stack>#include<cmath>#include<list>#include<map>#include<set>//#define DEBUGusing namespace std;typedef long long ll;const int N=10000;const double PI = acos(-1.0);const double EXP = 1E-8;const int INF = 0x3f3f3f3f;ll t,n,m,d;int main(){#ifdef DEBUGfreopen("input.in", "r", stdin);//freopen("output.out", "w", stdout);#endifscanf("%lld",&t);while(t--){scanf("%lld%lld%lld",&n,&m,&d);cout << n*m+n*(n-1)/2*d << endl;}//cout << "Hello world!" << endl;return 0;}
