poj2533Longest Ordered Subsequence LIS(优化)

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
const int N=1010;
const int inf=0x3fffffff;
int n,a[N],dp[N];

int binary_search(int aim[],int d,int length){
    int l=0,r=length,mid;
    while(l!=r){
        mid=(l+r)>>1;
        if(d == aim[mid]) return mid;
        else if(d < aim[mid]) r=mid;
        else l=mid+1;
    }
    return l;
}
int main()
{
    cin>>n;
    for(int i=1;i<=n;i++) scanf("%d",a+i);
    int len=1,j=1;
    dp[0]=-1;
    for(int i=1;i<=n;i++){
        dp[len]=inf;//与l=mid+1对应
        j=binary_search(dp,a[i],len);
        if(j == len) len++;
        dp[j]=a[i];
    }
    cout<<len-1<<endl;
    return 0;
}