1200: [HNOI2005]木梳 - BZOJ

 1 var
 2     a:array[0..100010]of longint;
 3     f:array[0..100010,-2..2,-1..1,0..1]of int64;
 4     h:array[0..100010,-2..2,-1..1]of longint;
 5     n:longint;
 6     ans:int64;
 7  
 8 function min(x,y:int64):int64;
 9 begin
10     if x<y then exit(x);
11     exit(y);
12 end;
13  
14 procedure init;
15 var
16     i:longint;
17 begin
18     read(n);
19     for i:=1 to n do
20       read(a[i]);
21     ans:=1<<60;
22     fillchar(f,sizeof(f),122);
23 end;
24  
25 procedure work;
26 var
27     i,j,k,j1,k1:longint;
28 begin
29     for j:=0 to 2 do
30       if 1+j<=n then
31       for k:=-1 to 1 do
32         if a[1+j]+k<=a[1] then
33         begin
34           h[1,j,k]:=a[1+j]+k;
35           f[1,j,k,0]:=a[1]-h[1,j,k];
36           f[1,j,k,1]:=a[1]-h[1,j,k];
37         end;
38     for i:=2 to n do
39       for j:=-2 to 2 do
40         if (i+j>0)and(i+j<=n) then
41         for k:=-1 to 1 do
42           if a[i+j]+k<=a[i] then
43           begin
44             h[i,j,k]:=a[i+j]+k;
45             for j1:=-2 to 2 do
46               for k1:=-1 to 1 do
47                 if h[i-1,j1,k1]>h[i,j,k] then f[i,j,k,0]:=min(f[i,j,k,0],f[i-1,j1,k1,1]+a[i]-h[i,j,k])
48                 else
49                   if h[i-1,j1,k1]<h[i,j,k] then f[i,j,k,1]:=min(f[i,j,k,1],f[i-1,j1,k1,0]+a[i]-h[i,j,k])
50                   else
51                     begin
52                       f[i,j,k,0]:=min(f[i,j,k,0],f[i-1,j1,k1,0]+a[i]-h[i,j,k]);
53                       f[i,j,k,1]:=min(f[i,j,k,1],f[i-1,j1,k1,1]+a[i]-h[i,j,k]);
54                     end;
55           end;
56     for j:=-2 to 0 do
57       for k:=-1 to 1 do
58         ans:=min(ans,min(f[n,j,k,0],f[n,j,k,1]));
59     write(ans);
60 end;
61  
62 begin
63     init;
64     work;
65 end.