poj 2533 Longest Ordered Subsequence(dp)

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

#define MAX(a,b) a>b?a:b
int a[1005], dp[1005], n;

int DP()
{
int i, j;

for (i = 1; i <= n; i++)
{
dp[i] = 1;
for (j = 1; j < i; j++)
{
if (a[i] > a[j])
dp[i] = MAX (dp[i], dp[j] + 1);
}
}
int ans = 0;
for (i = 1; i <= n; i++)
if (dp[i] > ans) ans = dp[i];
return ans;
}

int main()
{
scanf ("%d", &n);
if (n == 0)
{
printf ("1\n");
return 0;
}
for (int i = 1; i <= n; i++)
scanf ("%d", &a[i]);
printf ("%d\n",DP());
return 0;
}