A-A+

# Triangular Sums

2012年07月28日 阅读 107 次

## Triangular Sums

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)]`

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.

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.

```4
3
4
5
10```

```1 3 45
2 4 105
3 5 210
4 10 2145```

[cpp]
#include "iostream"
#include "stdlib.h"
using namespace std;
int main()
{
int temp,T,i,j,k,sumj,sum;
cin>>temp;
for(k=1;k<=temp;k++) { cin>>T;sum=0;
for(i=1;i<=T;i++) {sumj=0;for(j=1;j<=i+1;j++) sumj+=j;sum+=i*sumj;} cout<