hdu 5122 （2014北京现场赛 K题）

把一个序列按从小到大排序 要执行多少次操作

只需要从右往左统计，并且不断更新最小值，若当前数为最小值，则将最小值更新为当前数，否则sum+1

Sample Input
2
5
5 4 3 2 1
5
5 1 2 3 4

Sample Output
Case #1: 4
Case #2: 1

# include <iostream>
# include <cstdio>
# include <cstring>
# include <algorithm>
# include <string>
# include <cmath>
# include <queue>
# include <list>
# define LL long long
using namespace std ;

const int INF=0x3f3f3f3f;

int a[1000010] ;

int main()
{
    //freopen("in.txt","r",stdin) ;
    int T ;
    scanf("%d" , &T) ;
    int Case = 0 ;
    while(T--)
    {
        Case++ ;
        int n , i , j;
        scanf("%d" , &n) ;
        for (i = 0 ; i < n ; i++)
            scanf("%d" , &a[i]) ;
        int sum = 0 ;
        int MIN = INF ;
        for (i = n-1 ; i >=0 ; i--)
        {
            if (a[i] < MIN)
                MIN = a[i] ;
            else
                sum++ ;
        }
        printf("Case #%d: %d
" , Case , sum) ;


    }

    return 0 ;
}