zoj 1440

两种排序。不解释

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 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<algorithm>
 5 using namespace std;
 6 const long long maxn=500005;
 7 struct node
 8 {
 9     long long x;
10     long long i;
11 }e[maxn];
12 bool cmp(node a,node b)
13 {
14     return a.x<b.x;
15 }
16 bool vis[maxn];
17 long long c[maxn],t[maxn],n;
18 long long ans;
19 void dfs(long long i)
20 {
21     if(vis[i]) return;
22     vis[i]=1;
23     ans++;
24     dfs(e[i].i);
25     return;
26 }
27 int main()
28 {
29     while(scanf("%lld",&n)!=EOF)
30     {
31         for(long long i=0;i<=n;i++) e[i].x=e[i].i=0;
32         for(long long i=1;i<=n;i++)
33         {
34             scanf("%lld",&e[i].x);
35             e[i].i=i;
36         }
37         sort(e+1,e+n+1,cmp);
38         memset(vis,0,sizeof(vis));
39         ans=0;
40         for(long long i=1;i<=n;i++)
41             if(i!=e[i].i&&!vis[i])
42             {
43                 vis[i]=1;
44                 dfs(e[i].i);
45             }
46         printf("%lld\n",ans);
47         for(long long i=1;i<=n;i++)
48             t[e[i].i]=i;
49         memset(c,0,sizeof(c));
50         ans=0;
51         for(long long i=n;i>0;i--)
52         {
53             long long k=t[i];
54             while(k>0)
55             {
56                 ans+=c[k];
57                 k-=(k&-k);
58             }
59             k=t[i];
60             while(k<=n)
61             {
62                 c[k]++;
63                 k+=(k&-k);
64             }
65         }
66         printf("%lld\n",ans);
67     }
68     return 0;
69 }

转载于:https://www.cnblogs.com/xuschang-93/archive/2012/03/13/2394403.html