poj 1493 Machined Surfaces

#include<iostream>        
#include<string>
#include<algorithm>
using namespace std;
int main()
{
string str[20];
int blank[20],n,low,sum;
while(cin>>n&&n)
    {
        scanf("\n");
for(int i=0;i<n;++i)
        {
            getline(cin,str[i]);
            blank[i]=0;
for(int j=0;j<str[i].size();++j)
if(str[i][j]==' ')
                    blank[i]++;    
        }
        low=*min_element(blank,blank+n);
        sum=0;
for(int i=0;i<n;++i)
            sum+=blank[i]-low;        //每行的空格数减去最小空格数
        cout<<sum<<endl;
    }
return 0;

}