1 #include<cstdio>
 2 #include<cstring>
 3 #include<stdlib.h>
 4 #include<algorithm>
 5 using namespace std;
 6 int a[5005];
 7 int main()
 8 {
 9     int n,i,j;
10     while(scanf("%d",&n)!=EOF)
11     {
12         int sum=0;
13         for(i=0;i<n;i++)
14         {
15             scanf("%d",&a[i]);
16             for(j=0;j<i;j++)
17                 if(a[j]>a[i])
18                     sum++;
19         }
20         int ans=sum;
21         for(i=0;i<n;i++)
22         {
23             sum=sum-a[i]+(n-a[i]-1);
24             if(sum<ans)
25                 ans=sum;
26         }
27         printf("%d\n",ans);
28     }
29     return 0;
30 }

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<stdlib.h>
 4 #include<algorithm>
 5 using namespace std;
 6 struct node
 7 {
 8     int l,r;
 9     int num;
10     int mid()
11     {
12         return (l+r)>>1;
13     }
14 }a[5000*4];
15 int b[5005];
16 void btree(int l,int r,int step)
17 {
18     a[step].l=l;
19     a[step].r=r;
20     a[step].num=0;
21     if(l==r)  return ;
22     int mid=a[step].mid();
23     btree(l,mid,step*2);
24     btree(mid+1,r,step*2+1);
25 }
26 
27 void ptree(int step,int vis)
28 {
29     a[step].num++;
30     if(a[step].l==a[step].r)  return ;
31     int mid=a[step].mid();
32     if(vis>mid)
33         ptree(step*2+1,vis);
34     else
35         ptree(step*2,vis);
36 }
37 
38 int fintree(int step,int x,int y)
39 {
40     if(a[step].l==x&&a[step].r==y)
41         return a[step].num;
42     int mid=a[step].mid();
43     if(x>mid)
44         return fintree(step*2+1,x,y);
45     else if(y<=mid)
46         return fintree(step*2,x,y);
47     else
48         return fintree(step*2,x,mid)+fintree(step*2+1,mid+1,y);
49 }
50 int main()
51 {
52     int n,i,j;
53     while(scanf("%d",&n)!=EOF)
54     {
55         int ans=0;
56         btree(0,n-1,1);
57         for(i=0;i<n;i++)
58         {
59             scanf("%d",&b[i]);
60             ans+=fintree(1,b[i],n-1);
61             ptree(1,b[i]);
62         }
63         int minn=ans;
64         for(i=0;i<n;i++)
65         {
66             ans=ans-b[i]+(n-1-b[i]);
67             if(minn>ans) minn=ans;
68         }
69         printf("%d\n",minn);
70     }
71     return 0;
72 }