用来具体看哪个是最长的序列

#include <iostream>

using namespace std;

const int N = 1010;

int f[N], a[N], g[N];

int main()
{
    int n;
    cin >> n;

    for (int i = 1; i <= n; i ++) cin >> a[i];

    for (int i = 1; i <= n; i ++){
        f[i] = 1;
        g[i] = 0;
        for (int j = 0; j < i; j ++)
            if (a[j] < a[i])
                if (f[i] < f[j] + 1)
                {
                    f[i] = f[j] + 1;
                    g[i] = j;
                }
    }
    int k = 1;
    for (int i = 1; i <= n; i ++)
        if (f[i] > f[k]) 
            k = i;
    cout << f[k] << endl;

    for (int i = 0, len = f[k]; i < len; i ++)
    {
        cout << a[k] << " ";
        k = g[k];

    }


    return 0;
}