Triangular Sums
时间限制: 3000 ms | 内存限制:65535 KB
难度: 2
- 描述
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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 XWrite 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
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434510
样例输出 -
1 3 452 4 1053 5 2104 10 2145
来源 - 上传者
- 题目:比如这个三角形有4层,他的第一层为1.....第四层为4,T(n)=1+2+3+4;但是他不是让我们求T(n),让我们求W(n),W(n)=k*T(k+1); (k=1,2,....n);
- 然后输出的这三位分别是:第一位 1-t(t是多少组测试数据),第二位是 n(就是你输入的n),第三位是 W(n),(英语不好,别见怪哈~) 具体看代码实现:
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#include
//用来求T(n),1+2+3+...n;int f(int n){ int i,ans; ans=0; for(i=1;i<=n;i++) ans+=i; return ans;}int main(){ int t,a; a=1; //用来计1到t; scanf("%d",&t); while(t--) { int i,n,k,ans; ans=0; k=1; scanf("%d",&n); //用来求W(n) for(i=0;i