Triangular Sums
时间限制：
3000 ms | 内存限制：
65535 KB
难度：
2
- 描述
-
The nth Triangular number, T(n) = 1 + … + n, is the sum of the first n integers. It is the number of points in a triangular array with n points on side. For example T(4):
X
X X
X X X
X X X X
Write a program to compute the weighted sum of triangular numbers:
W(n) =
SUM[k = 1…n; k * T(k + 1)]- 输入
-
The first line of input contains a single integer N, (1 ≤ N ≤ 1000) which is the number of datasets that follow.
Each dataset consists of a single line of input containing a single integer n, (1 ≤ n ≤300), which is the number of points on a side of the triangle. - 输出
- For each dataset, output on a single line the dataset number (1 through N), a blank, the value of n for the dataset, a blank, and the weighted sum ,W(n), of triangular numbers for n.
- 样例输入
-
4 3 4 5 10
- 样例输出
-
1 3 45 2 4 105 3 5 210 4 10 2145
01.
#include <iostream>
02.
using namespace std;
03.
04.
int main()
05.
{
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int testNum;
07.
cin >> testNum;
08.
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for (int sample = 1; sample <= testNum; sample++)
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{
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long w = 0;
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int n;
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cin >> n;
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for (int k = 1; k <= n; k++)
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{
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//等差公式
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w += k * ((1+(k+1)) * (k+1) / 2);
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}
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cout << sample << " " << n << " " << w << endl;
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}
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return 0;
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}
