BZOJ 1609 [Usaco2008 Feb]Eating Together麻烦的聚餐：LIS & LDS (nlogn)

 1 #include <iostream>
 2 #include <stdio.h>
 3 #include <string.h>
 4 #define MAX_N 30005
 5 
 6 using namespace std;
 7 
 8 int n;
 9 int a[MAX_N];
10 int d[MAX_N];
11 
12 int cal_lis()
13 {
14     int len=1;
15     d[1]=a[0];
16     for(int i=1;i<n;i++)
17     {
18         if(a[i]>=d[len])
19         {
20             d[++len]=a[i];
21             continue;
22         }
23         int lef=1;
24         int rig=len;
25         while(rig-lef>1)
26         {
27             int mid=(lef+rig)/2;
28             if(a[i]>=d[mid]) lef=mid;
29             else rig=mid;
30         }
31         int ans;
32         if(a[i]<d[lef]) ans=0;
33         else ans=lef;
34         d[ans+1]=min(d[ans+1],a[i]);
35     }
36     return len;
37 }
38 
39 int cal_lds()
40 {
41     int len=1;
42     d[1]=a[0];
43     for(int i=1;i<n;i++)
44     {
45         if(a[i]<=d[len])
46         {
47             d[++len]=a[i];
48             continue;
49         }
50         int lef=1;
51         int rig=len;
52         while(rig-lef>1)
53         {
54             int mid=(lef+rig)/2;
55             if(a[i]<=d[mid]) lef=mid;
56             else rig=mid;
57         }
58         int ans;
59         if(a[i]>d[lef]) ans=0;
60         else ans=lef;
61         d[ans+1]=max(d[ans+1],a[i]);
62     }
63     return len;
64 }
65 
66 int main()
67 {
68     cin>>n;
69     for(int i=0;i<n;i++)
70     {
71         cin>>a[i];
72     }
73     int v1=cal_lis();
74     int v2=cal_lds();
75     cout<<n-max(v1,v2)<<endl;
76 }