ACM - UVA 103 - Stacking Boxes

Problem: 103 - Stacking Boxes
Solution: C++
Hints: http://www.algorithmist.com/index.php/UVa_103

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <string>
#include <cctype>
#include <stack>
#include <queue>
#include <list>
#include <vector>
#include <map>
#include <sstream>
#include <utility>
#include <set>
#include <math.h>
using namespace std;
 
struct node {   
    int id;
    int d [12];
} a [32];

int k;
int n;
int best [32];
int parent [32];
vector <int> v;

bool cmp (int x, int y)
{
    for ( int i = 0; i < n; i++ ) 
   {
        if ( a [x].d [i] <= a [y].d [i] )
            return false;
    }
    return true;
}

void print_path (int x)
{
    if ( x == parent [x] )
        return ;
    print_path (parent [x]);
    v.push_back (a [parent [x]].id);
}

 int lis ()
{
    for ( int i = 0; i < k; i++ )
   {
        best [i] = 1;
        parent [i] = i;
    }

    for ( int i = 1; i < k; i++ )
   {
        for ( int j = 0; j < i; j++ )
       {
            if ( cmp (i, j) && best [i] < best [j] + 1 )
            {
                best [i] = best [j] + 1;
                parent [i] = j;
            }
        }
    }

    int index;
    int max = 0;
    for ( int i = 0; i < k; i++ )
   {
        if ( max < best [i] )
       {
            max = best [i];
            index = i;
        }
    }
    print_path (index);
    v.push_back (a [index].id);
    return max;
}


int main ()
{  
   while ( scanf ("%i %i", &k, &n) != EOF )
   {
        v.clear ();
        for ( int i = 0; i < k; i++ )
       {
            a [i].id = i + 1;
            for ( int j = 0; j < n; j++ )
                scanf ("%d", &a [i].d [j]);
            sort (a [i].d, a [i].d + n );
        }

        // bubble sort
        for ( int i = 0; i < k; i++ )
       {
            for ( int j = i + 1; j < k; j++ )
           {
                    if ( cmp (i, j) )
                        swap (a [i], a [j]);
            }
        }

        printf ("%d\n", lis ());
        for ( unsigned int i = 0; i < v.size (); i++ )
       {
            if ( i != 0 )
                printf (" ");
            printf ("%d", v.at (i));
        }
        printf ("\n");
    }
    return 0;
}