51Nod 1134 最长递增子序列（动态规划O(nlogn)）

#include <iostream>
#include <algorithm>
#include <stdio.h>
#define MAXN 50010
using namespace std;

const int MIN = -1e9;

int main(void){
    int n, a[MAXN], vis[MAXN], len = 1; 
    scanf("%d", &n);
    for (int i = 0; i<n; i++){
        scanf("%d", &a[i]);
    }
    for (int i = 0; i <= n; i++){
        vis[i] = MIN;
    }

    //vis[i]表示满足递增数量i的最小值 
    vis[1] = a[0];
    for (int i = 1; i<n; i++){
        //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
        int pos = upper_bound(vis + 1, vis + len + 1, a[i]) - vis;
        vis[pos] = a[i];
        if (len<pos){ //维护最大长度
            len = pos;
        }
    }
    printf("%d
", len);
    return 0;
}