1045 Favorite Color Stripe (30)（30 分）

转化为最大不下降子列长度

#include
#include
using namespace std;
const int maxn = 1e4 + 10;
int order[maxn], a[maxn], dp[maxn], n, m, l;
int main()
{
    scanf("%d", &n);
    scanf("%d", &m);
    fill(order, order + maxn, -1);
    for (int i = 1; i <= m; i++)
    {
        int x;
        scanf("%d", &x);
        order[x] = i;
    }
    scanf("%d", &l);
    int cnt = 0;
    for (int i = 0; i < l; i++)
    {
        int x;
        scanf("%d", &x);
        if (order[x] == -1)continue;
        a[cnt++] = order[x];
    }
    int ans = 0;
    for (int i = 0; i < cnt; i++)
    {
        dp[i] = 1;
        for (int j = 0; j < i; j++)
        {
            if (a[j]<=a[i] && dp[j] + 1>dp[i])
            {
                dp[i] = dp[j] + 1;
            }
        }
        ans = max(ans, dp[i]);
    }
    int k = 0;
    for (int i = 0; i < cnt; i++)
    {
        if (dp[i] > dp[k])k = i;
    }
    printf("%d", dp[k]);
    return 0;
}