poj3903

最长上升子序列

#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

#define maxn 100005

int n;
int top;
int stk[maxn];

int binarysearch(int l, int r, int a)
{
    if (l > r)
        return l;
    if (a > stk[r])
        return r + 1;
    while (l < r)
    {
        int mid = (l + r) / 2;
        if (stk[mid] < a)
            l = mid + 1;
        else
            r = mid;
    }
    return l;
}

int main()
{
    //freopen("t.txt", "r", stdin);
    while (scanf("%d", &n) != EOF)
    {
        top = 0;
        for (int i = 0; i < n; i++)
        {
            int a;
            scanf("%d", &a);
            int index = binarysearch(0, top - 1, a);
            stk[index] = a;
            top = max(top, index + 1);
        }
        printf("%d\n", top);
    }
    return 0;
}