POJ 2533 Longest Ordered Subsequence 最长上升子序列

int LISOnlogn(int a[],int tot)
{
    int len=1;
    dp[1]=a[1];
    for(int i=2; i<=tot; i++)
    {
        if(a[i]>dp[len])
            dp[++len]=a[i];
        else
        {
            int r=len,l=1;
            while(r>=l)
            {
                int mid=(r+l)/2;
                if(a[i]>=dp[mid])
                    l=mid+1;
                else r=mid-1;
            }
            dp[l]=a[i];
        }
    }
    return len;
}

#include <iostream>
#include <cstdio>
#define maxn 1005
using namespace std;
int a[maxn],dp[maxn],head[maxn],lis[maxn];
int LISOnlogn(int a[],int tot)
{
    int len=1;
    dp[1]=a[1];
    for(int i=2; i<=tot; i++)
    {
        if(a[i]>dp[len])
            dp[++len]=a[i];
        else
        {
            int r=len,l=1;
            while(r>=l)
            {
                int mid=(r+l)/2;
                if(a[i]>=dp[mid])
                    l=mid+1;
                else r=mid-1;
            }
            dp[l]=a[i];
        }
    }
    return len;
}
int LISOn2(int a[],int tot)
{
    for(int i=1; i<=tot; i++)
    {
        dp[i]=1;
        head[i]=-1;
    }
    for(int i=1; i<=tot; i++)
    {
        int m=0,h=-1;
        for(int j=1; j<i; j++)
        {
            if(a[i]>a[j]&&dp[j]>m)
            {
                m=dp[j];
                h=j;
            }
            dp[i]=m+1;
            head[i]=h;
        }
    }
    int ans=0,pos=0;
    for(int i=1; i<=tot; i++)
    {
        if(dp[i]>ans)
        {
            ans=dp[i];
            pos=i;
        }
    }
    int top=0;
    for(int i=pos; i!=-1; i=head[i])
    {
        lis[top++]=a[i];
    }
    return ans;
}
int main()
{
    int tot;
    scanf("%d",&tot);
    for(int i=1; i<=tot; i++)
        scanf("%d",&a[i]);
    int ans=LISOn2(a,tot);
    //ans=LISOnlogn(a,tot);
    cout<<ans<<endl;
    return 0;
}