洛谷 AT2827 LIS

题目传送门

解题思路:

用f[i]表示长度为i的最长上升子序列的最小的末尾.

AC代码:

 #include<iostream>
 #include<cstdio>
 #include<algorithm>

 using namespace std;

 int n,a[],f[],len = ;

 int main() {
     scanf("%d",&n);
     for(int i = ;i <= n; i++)
         scanf("%d",&a[i]);
     f[] = a[];
     for(int i = ;i <= n; i++)
         if(a[i] > f[len])
             f[++len] = a[i];
         else {
             int u = lower_bound(f+,f+len+,a[i]) - f;
             f[u] = a[i];
         }
     printf("%d",len);
     return ;
 }