L2-014. 列车调度

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<set>
#include<vector>
#include<algorithm>

using namespace std;
const int maxn=1007;
const int INF=0x3f3f3f3f;

int main()
{
    int n, num;
    set<int>s;
    set<int>::iterator it;
    scanf("%d", &n);
    while(n--)
    {
        scanf("%d", &num);
        if(s.empty())
            s.insert(num);
        else
        {
            it=s.lower_bound(num);
            if(it==s.end())
                s.insert(num);
            else
            {
                s.erase(it);
                s.insert(num);
            }
        }
    }
    printf("%d\n", s.size());
    return 0;
}