POJ2127 编程问题求解

样例和自己找的所有例子例子都过了，还是WA，求大神们解答！
谢谢！

#include<iostream>
#include<algorithm>
using namespace std;
int n1 = 0, n2 = 0;
int a1[505] = { 0 }, a2[505] = { 0 };
int ans[505][505] = { 0 };
int MAX = 0;
void print(int k, int cnt)
{
    if (cnt == 1)
    {
        cout << a1[k];
        if (cnt == MAX) cout << endl;
        else cout << " ";
        return;
    }
    for (int i = k - 1; i > 0; --i)
    {
        if (a1[k] > a1[i] && ans[k][n2] == 1 + ans[i][n2])
        {
            print(i, cnt - 1);
            cout << a1[k];
            if (cnt == MAX) cout << endl;
            else cout << " ";
            return;
        }
    }
}
int main()
{
    cin >> n1;
    for (int i = 1; i <= n1; ++i)
        cin >> a1[i];
    cin >> n2;
    for (int i = 1; i <= n2; ++i)
        cin >> a2[i];
    for (int i = 1; i <= n1; ++i)
    {
        for (int j = 1; j <= n2; ++j)
        {
            if (a1[i] == a2[j])
            {
                ans[i][j] = 1;
                for (int k = i - 1; k >= 1; --k)
                {
                    if (a1[i] > a1[k] && ans[i][j] < ans[k][j] + 1)
                        ans[i][j] = ans[k][j] + 1;
                }
                MAX = max(MAX, ans[i][j]);
            }
            else ans[i][j] = ans[i][j - 1];
        }
    }
    cout << MAX << endl;
    if (MAX)
    {
        for (int i = n1; i > 0; --i)
        {
            if (MAX == ans[i][n2])
            {
                print(i, MAX);
                break;
            }
        }
    }
    else cout << endl;
    system("pause");
    return 0;
}

在oj上不要用system("pause");