nyoj 122 Triangular Sums

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

434510

样例输出

1 3 452 4 1053 5 2104 10 2145

题目大意：给出一个数，求出这个数的sum值，sum等于k*（T（k+1）），T（k+1)=1+2+，，，k+1；输出第几次情况，输入数的值，以及sum值
思路：写个小函数
2014,12,13

#include<stdio.h>int Sum(int a){int s=0,i;for(i=1;i<=a+1;i++)s+=i;s*=a;return s;}int main(){int N,k,i,sum,c=1;scanf("%d",&N);while(N--){scanf("%d",&k);sum=0;for(i=1;i<=k;i++)sum+=Sum(i);printf("%d %d %d\n",c++,k,sum);}return 0;}