Box of Bricks ——平均数问题

Box of Bricks

Little Bob likes playing with his box of bricks. He puts the bricks one upon another and builds stacks of different height. ``Look, I've built a wall!'', he tells his older sister Alice. ``Nah, you should make all stacks the same height. Then you would have a real wall.'', she retorts. After a little con- sideration, Bob sees that she is right. So he sets out to rearrange the bricks, one by one, such that all stacks are the same height afterwards. But since Bob is lazy he wants to do this with the minimum number of bricks moved. Can you help?

Input 

The input consists of several data sets. Each set begins with a line containing the number  n  of stacks Bob has built. The next line contains n  numbers, the heights  h _i  of the  n  stacks. You may assume   and  .

The total number of bricks will be divisible by the number of stacks. Thus, it is always possible to rearrange the bricks such that all stacks have the same height.

The input is terminated by a set starting with n = 0. This set should not be processed.

Output 

For each set, first print the number of the set, as shown in the sample output. Then print the line ``  The minimum number of moves is k .'', where  k  is the minimum number of bricks that have to be moved in order to make all the stacks the same height.

Output a blank line after each set.

Sample Input 

6
5 2 4 1 7 5
0

Sample Output 

Set #1
The minimum number of moves is 5.

题意很简单，将不等高的数列通过移动砖快改变成等高的，求移动砖块的最少数目。

这道题目的关键就在于想到无论怎么变换，最后的高度都是总的高度除以N,所以只需要求平均数计算出平均高度，然后将超出平均高度的砖移向低于平均高度的地方就可以了。

这样，问题就转换成了求高于平均高度的砖的数目。

不过需要注意的是，每一组数据结束之后有一个空行！！！

#include <stdio.h>
#include <string.h>

int main()
{
    int sum,cha,wall[60],adv;
    int n,i = 1,j;
    while(scanf("%d",&n),n)
    {
        sum = 0;
        for(j = 0;j < n;j++)
        {
            scanf("%d",&wall[j]);
            sum += wall[j];
        }
        adv = sum / n;
        cha = 0;
        for(j = 0;j < n;j++)
        {
            if(wall[j] > adv)
                cha += wall[j] - adv;
        }
        printf("Set #%d\n",i);
        printf("The minimum number of moves is %d.\n\n",cha);
        i++;
    }
    return 0;
}