51Nod 1134 最长递增子序列（动态规划O(nlogn)）

 1 #include <iostream>
 2 #include <algorithm>
 3 #include <stdio.h>
 4 #define MAXN 50010
 5 using namespace std;
 6 
 7 const int MIN = -1e9;
 8 
 9 int main(void){
10     int n, a[MAXN], vis[MAXN], len = 1; 
11     scanf("%d", &n);
12     for (int i = 0; i<n; i++){
13         scanf("%d", &a[i]);
14     }
15     for (int i = 0; i <= n; i++){
16         vis[i] = MIN;
17     }
18 
19     //vis[i]表示满足递增数量i的最小值 
20     vis[1] = a[0];
21     for (int i = 1; i<n; i++){
22         //upper_bound(vis + 1, vis + len + 1, a[i]) 返回被查序列中第一个大于查找值的指针
23         int pos = upper_bound(vis + 1, vis + len + 1, a[i]) - vis;
24         vis[pos] = a[i];
25         if (len<pos){ //维护最大长度
26             len = pos;
27         }
28     }
29     printf("%d\n", len);
30     return 0;
31 }