最长升序子序列

 1 #include<iostream>
 2 #include<cstdio>
 3 using namespace std;
 4 #define  maxn 100000+10
 5 int al[maxn], cl[maxn];
 6 int main()
 7 {
 8     int n,len,left,right,mid;
 9     while (scanf("%d",&n)!= EOF){
10         for (int i = 0; i < n; i++)
11             scanf("%d", &al[i]);
12         len = 0, cl[0] = -1;
13         for (int i = 0; i < n; i++)
14         {
15             if (al[i]>cl[len])
16                 cl[++len] = al[i];    //把大的数放进去
17             else
18             {
19                 left = 1, right = len;    //二分法找后面小的数放在这个子序列的前面，以免有更长的子序列
20                 
21                 while (left <= right)
22                 {
23                     mid = (left + right) / 2;
24                     if (al[i]>cl[mid])
25                         left = mid + 1;
26                     else
27                        right = mid - 1;
28                 }
29                 cl[left] = al[i];
30             }
31         }
32         printf("%d\n", len);
33     }
34     
35     return 0;
36 }