最长递增子序列

#include 
      
       #include 
       
        #include 
        
         #include 
         
          using namespace std;#define maxn 40004int n;int f[maxn];int d[maxn];int m;void input(){    scanf("%d", &n);    for (int i = 0; i < n ;i++)        scanf("%d", &f[i]);}int binarysearch(int a){    int l = 0;    int r = m;    while (l < r)    {        int mid = (l + r) / 2;        if (d[mid] < a)            l = mid + 1;        else            r = mid;    }    if (l >= m)        m++;    return l;}int work(){    m = 0;    for (int i = 0; i < n; i++)        d[binarysearch(f[i])] = f[i];    return m;}int main(){    input();    printf("%d\n", work());    return 0;}