BZOJ1049: [HAOI2006]数字序列

题目：http://www.lydsy.com/JudgeOnline/problem.php?id=1049

题解：

ydc的题解：http://pan.baidu.com/share/link?uk=2651016602&shareid=1490516411

第二问比较神？考场上敢去猜结论？

代码：

#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<cstring>
#include<algorithm>
#include<iostream>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<string>
#define inf 1000000000
#define maxn 50000+5
#define maxm 100000+5
#define eps 1e-10
#define ll long long
#define pa pair<int,int>
#define for0(i,n) for(int i=0;i<=(n);i++)
#define for1(i,n) for(int i=1;i<=(n);i++)
#define for2(i,x,y) for(int i=(x);i<=(y);i++)
#define for3(i,x,y) for(int i=(x);i>=(y);i--)
#define for4(i,x) for(int i=head[x],y=e[i].go;i;i=e[i].next,y=e[i].go)
#define mod 1000000007
using namespace std;
inline int read()
{
int x=0,f=1;char ch=getchar();
while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
while(ch>='0'&&ch<='9'){x=10*x+ch-'0';ch=getchar();}
return x*f;
}
int n,a[maxn],b[maxn],f[maxn],next[maxn],last[maxn];
ll g[maxn],t[maxn];
int main()
{
freopen("input.txt","r",stdin);
freopen("output.txt","w",stdout);
n=read();
for1(i,n+2)b[i]=inf;
for2(i,2,n+1)a[i]=read()-i;
a[1]=-inf;a[n+2]=inf-1;
n+=2;
for1(i,n)
{
f[i]=upper_bound(b+1,b+n+1,a[i])-b;
b[f[i]]=a[i];
}
cout<<n-f
<<endl;
for3(i,n,1)next[i]=last[f[i]],last[f[i]]=i;
memset(g,127,sizeof(g));
for1(i,n)
{
if(f[i]==1){g[i]=0;continue;}
t[i]=0;
for3(j,i-1,last[f[i]-1])t[j]=t[j+1]+abs(a[j]-a[i]);
for(int j=last[f[i]-1];j;j=next[j])if(a[j]<=a[i])
{
if(j+1==i){g[i]=min(g[i],g[j]);continue;}
ll tot=0;
for2(k,j,i-1)
{
tot+=abs(a[j]-a[k]);
g[i]=min(g[i],g[j]+tot+t[k+1]);
}
}
}
cout<<g
<<endl;
return 0;
}

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