HDU 1950 Bridging signals

http://acm.hdu.edu.cn/showproblem.php?pid=1950
LIS问题:O(nlog(n))二分的算法

#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
using namespace std;
const int lmax=40005;

int a[lmax],dp[lmax];
int main()
{
    //freopen("1.txt","r",stdin);
    int T,n,i,j,k;
    scanf("%d",&T);
    while(T--)
    {
        scanf("%d",&n);
        for(i=1;i<=n;i++) scanf("%d",a+i);
        int len=0,ans=0;
       
        for(i=1;i<=n;i++)
        {
            int lft=1,rht=len,mid;
            while(lft<=rht)
            {
                mid=(lft+rht)/2;
                if(dp[mid]<a[i]) lft=mid+1;
                else rht=mid-1;
            }
            dp[lft]=a[i];
            if(len<lft) len=lft;
            if(ans<len) ans=len;
        }
        /*
        for(i=1;i<=n;i++)
        {
            int k=lower_bound(dp,dp+len,a[i])-dp;
            dp[k++]=a[i];
            if(len<k) len=k;
            if(ans<len) ans=len;
        }
        */
        printf("%d\n",ans);
    }
}