[Maximize ∑arr[i]*i of an Array]

Given an array of N integers. Your task is to write a program to find the maximum value of ∑arr[i]*i, where i = 0, 1, 2,…., n – 1.
You are allowed to rearrange the element of the array

Examples:

Input : N = , arr[] = { , , ,  }
Output :
If we arrange arr[] , , ,  }.
Sum of arr[i]*i * + * + * + *
= , which is maximum

Input : N = , arr[] = { ,  }
Output : 

Note: Since output could be large, hence module 10^9+7 and then print answer.
Input:
First line of the input contains an integer T, denoting the number of test cases. Then T test case follows. First line of each test case contains an integer N, denoting the size of the array. Next line contains N space separated integers denoting the elements of the array.

Output:
For each test case print the required answer on a new line.

Constraints:
1<=T<=103
1<=N<=103

Example:
Input:
2
5
5 3 2 4 1
3
1 2 3
Output:
40
8

下面是我的代码实现：思路：先对数组进行升序排列，然后按着公式即是最大值。我就奇了怪了，我的代码应该是没问题的，在OJ上出现了不可理解的错误：

代码如下：

#include <bits/stdc++.h>
using namespace std;

int main()
{
    int num,i;
    cin>>num;
    for(i=0;i<num;i++)
    {
        int N,j,k,temp;
        long sum=0;
        cin>>N;
        int *Arr=new int[N];
        for(j=0;j<N;j++)
            cin>>Arr[j];
        for(j=0;j<N;j++)
        {
            for(k=0;k<N;k++)
            {
                if(Arr[k]>Arr[k+1])
                {
                    temp=Arr[k];
                    Arr[k]=Arr[k+1];
                    Arr[k+1]=temp;
                }
            }
        }
        for(j=0;j<N;j++)
            sum=sum+j*Arr[j];
        cout<<sum<<endl;
    }
    return 0;
}

　　然后提交，反馈是：

Wrong Answer. !!!Wrong Answer
Possibly your code doesn't work correctly for multiple test-cases (TCs).
The first test case where your code failed:

Input:

Its Correct output is:

And Your Code's output is:

但是我在本地运行的这个例子的答案是：237220

就是不明白为什么在OJ上就是233266，好气哦