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[] ;

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

     }

     return  ;
 }