hdu 5122 K.Bro Sorting

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 #define maxn 1000100
 5 using namespace std;
 6 
 7 int t,n;
 8 int c[maxn];
 9 int a[maxn];
10 
11 int lowbit(int x)
12 {
13     return x&-x;
14 }
15 
16 void insert(int x,int y)
17 {
18     while(x<maxn)
19     {
20         c[x]+=y;
21         x+=lowbit(x);
22     }
23 }
24 
25 int Getsum(int x)
26 {
27     int ans=0;
28     while(x>0)
29     {
30         ans+=c[x];
31         x-=lowbit(x);
32     }
33     return ans;
34 }
35 int main()
36 {
37       scanf("%d",&t);
38       for(int cas=1; cas<=t; cas++)
39       {
40           memset(c,0,sizeof(c));
41           memset(a,0,sizeof(a));
42           scanf("%d",&n);
43           for(int i=0; i<n; i++)
44           {
45               scanf("%d",&a[i]);
46           }
47           int ans=0;
48           for(int i=n-1; i>=0; i--)
49           {
50               int xx=Getsum(a[i]-1);
51               if(xx!=0)
52               ans++;
53               insert(a[i],1);
54           }
55           printf("Case #%d: %d\n",cas,ans);
56       }
57       return 0;
58 }