UVA 103-Stacking Boxes

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#define MAXN 30+5
int a[MAXN][15],f[MAXN],m[MAXN][MAXN],r[MAXN],w[MAXN];
int k, n, ok;
int flag;
int cmp1(const void *_p,const void *_q)
{
    int *p = (int *)_p;
    int *q = (int *)_q;
    return *p - *q;
}
int cmp2(const void *_p,const void *_q)
{
    int *p = (int *)_p;
    int *q = (int *)_q;
    return a[*p][1] - a[*q][1];
}
void com(int i, int j)
{
    for(int p = 1; p <= n; p ++)
        if(a[r[i]][p] >= a[r[j]][p]) return;
    ok = 1;    
}
void dp(int i)
{
    if(w[i] == -1) ;
    else dp(w[i]);
    if(w[i] == -1)
        printf("%d",r[i]);
    else printf(" %d",r[i]);    
}
void solve()
{
    memset(m,-1,sizeof(m));
    memset(f,0,sizeof(f));
    memset(w,-1,sizeof(w));
    for(int i = 0; i < MAXN; i ++)
        f[i] = 1;
    for(int i = 1; i <= k; i ++)
        {
            int q = 0;
            for(int j = i +1; j <= k; j ++)
            {
                ok = 0;
                com(i,j);//printf("i=%d j=%d ok=%d
",i,j,ok);
                if(ok&&f[j]<f[i]+1) {f[j] = f[i] + 1;w[j] = i;}
            //    printf("f[i]=%d f[j] = %d w[j] = %d
",f[i],f[j],w[j]);
            }
        }
        int max = -1;
        for(int i = 1; i <= k; i ++)
            if(f[i] > max) {max = f[i];flag = i;}
        printf("%d
",max);
        //for(int i = 0; i <= k; i ++)
    //    printf("i = %d w[i] = %d
",i,w[i]);
        dp(flag);
        printf("
");
}
void input()
{
    memset(a,0,sizeof(a));
    while(scanf("%d%d",&k,&n) == 2)
    {
        for(int i = 1; i <= k; i ++)
            for(int j = 1; j <= n; j ++)
                scanf("%d",&a[i][j]);
        for(int i = 1; i <= k; i ++)
            qsort(a[i],n+1,sizeof(a[1][1]),cmp1);
        for(int i = 0; i <= k; i ++)
            r[i] = i;
        qsort(r,k+1,sizeof(r[0]),cmp2);
        solve();
    }
}
int main()
{
    input();
    return 0;
}