nyoj 122 Triangular Sums

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Triangular Sums

时间限制：3000 ms | 内存限制：65535 KB

难度：2

描述

The n^th 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

样例输出

1 3 452 4 1053 5 2104 10 2145

来源

Greater New York 2006

#include<stdio.h>
int main()
{
int t,n,i,j,sum,k;
scanf("%d",&t);
for(k=1;k<=t;k++)
{
  sum=0;
  scanf("%d",&n);
  for(i=1;i<=n;i++)
  {
   for(j=1;j<=i+1;j++)
   {
    sum+=i*j;
   }
  }
  printf("%d %d %d\n",k,n,sum);
}
return 0;
}

/*此题和三角形无关，就是求公式的和：
即给你一个n，k=1,2···,n时
依次求k*T(k+1)的积，再相加
【其中T(n) = 1 + … + n】*/

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