uva 10534

一开始WA了  参考了一下   求正反两个方向的最长上升子序列  并分别记录在两个数组中  最后求最大值

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

int a[10010],c1[10010],c2[10010],d[10010];
int cc(int n, int& i)
{
    if(i == 0 || d[i] < n)
    {
        d[++i] = n;
    }
    else
    {
        int p = lower_bound(d, d+i, n) - d;
        d[p] = n;
    }
    return i;
}
int main()
{
    int n;
    while(scanf("%d",&n) == 1)
    {
        memset(c1, 0, sizeof(c1));
        memset(c2, 0, sizeof(c2));
        int c = 0, _max = 0;
        for(int i = 0; i < n; i++)
        {
            scanf("%d",&a[i]);
            c1[i] = cc(a[i], c);
        }
        c = 0;
        for(int i = n-1; i >= 0; i--)
        {
            c2[i] = cc(a[i],c);
        }
        for(int i = 0; i < n; i++)
        {
            _max = max(_max, min(c1[i], c2[i]));
        }
        printf("%d\n",_max*2-1);
    }
    return 0;
}