Lưu ý: Các code mẫu dưới đây chỉ mang tính tham khảo và có thể không AC được bài tập này

Code mẫu của ladpro98

#include <iostream>
#include <cstdio>
#include <iomanip>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <climits>
#include <numeric>
#include <vector>
#include <queue>
#include <map>
#include <utility>
#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define REP(i, a, b) for(int i = (a); i <=(b); i++)
#define FORD(i, a, b) for(int i = (a); i > (b); i--)
#define REPD(i, a, b) for(int i = (a); i >=(b); i--)
#define SZ(a) (int((a).size()))
#define ALL(a) (a).begin(), a.end()
#define PB push_back
#define MP make_pair
#define LL long long
#define LD long double
#define II pair<int, int>
#define X first
#define Y second
#define VI vector<int>
const int N = 50050;
const int lim = 1e6 + 6;
using namespace std;
int a[N], F[lim];
int n, num;
VI ans[N];

int main() {
    ios :: sync_with_stdio(0); cin.tie(0);
    cin >> n;
    REP(i, 1, n) cin >> a[i];
    sort(a + 1, a + 1 + n);
    REP(i, 1, n) {
        if (a[i] == a[i - 1]) F[a[i]]++;
        else {
            int srt = min(int(sqrt(a[i])) + 1, max(a[i] - 1, 1));
            REP(j, 1, srt)
            if (a[i] % j == 0)
                F[a[i]] = max(F[a[i]], max(F[j], F[a[i] / j]) + 1);
        }
        ans[F[a[i]]].PB(a[i]);
        num = max(num, F[a[i]]);
    }
    cout << num << '\n';
    REP(i, 1, num) {
        cout << int(SZ(ans[i])) << ' ';
        FOR(j, 0, SZ(ans[i]))
            cout << ans[i][j] << ' ';
        cout << '\n';
    }
    return 0;
}

Code mẫu của RR

//Written by RR
{$R-,Q-}
{$Mode objfpc}
{$inline on}

uses math;
const
  FINP          =       '';
  FOUT          =       '';
  MAXN          =       50111;
  oo            =       1000111;
type
  Llist         =       ^node;
  node          =       record
                                u:longint;
                                next:Llist;
                        end;
var
  f1,f2         :       text;
  n             :       longint;
  a,f           :       array[1..MAXN] of longint;
  pos           :       array[1..oo] of longint;
  list          :       array[1..MAXN] of Llist;
  size          :       array[1..MAXN] of longint;
  p,lt          :       array[1..MAXN] of longint;

const
  MAXV          =       1000;
  MAXP          =       trunc((MAXV/ln(MAXV))*150/100);

var
  dd            :       array[1..MAXV] of byte;
  prime         :       array[1..MAXP] of longint;
  sprime        :       longint;

procedure generate;
    var
      i,j,gh:longint;
    begin
      gh:=trunc(sqrt(MAXV));
      for i:=2 to gh do
      if dd[i]=0 then
        begin
          inc(sprime);
          prime[sprime]:=i;
          j:=i*i;
          while j<=MAXV do
            begin
              dd[j]:=1;
              inc(j,i);
            end;
        end;

      for i:=gh+1 to MAXV do
        if dd[i]=0 then
          begin
            inc(sprime);
            prime[sprime]:=i;
          end;
    end;

procedure openF;
    begin
      assign(f1,FINP); reset(f1);
      assign(f2,FOUT); rewrite(f2);
    end;
procedure closeF;
    begin
      close(f1);
      close(f2);
    end;
procedure add(u:longint; var a:Llist); inline;
    var
      p:Llist;
    begin
      new(p); p^.u:=u;
      p^.next:=a; a:=p;
    end;
procedure swap(var a,b:longint); inline;
    var
      temp:longint;
    begin
      temp:=a; a:=b; b:=temp;
    end;
procedure sort(l,r:longint); inline;
    var
      i,j,mid:longint;
    begin
      i:=l; j:=r; mid:=a[l+random(r-l+1)];
      repeat
        while a[i]<mid do inc(i);
        while a[j]>mid do dec(j);
        if i<=j then
          begin
            swap(a[i],a[j]);
            inc(i); dec(j);
          end;
      until i>j;
      if i<r then sort(i,r);
      if l<j then sort(l,j);
    end;
procedure inp;
    var
      i:longint;
    begin
      read(f1,n);
      for i:=1 to n do
        read(f1,a[i]);
    end;

var
  sp,now        :       longint;

procedure duyet(i,k:longint); inline;
    var
      j,jj,save:longint;
    begin
      jj:=1; save:=now;
      for j:=0 to lt[i] do
        begin
          if i<sp then duyet(i+1,k)
          else
              if pos[now]>0 then f[k]:=max(f[k],f[pos[now]]+1);
          now:=now*p[i];
        end;
      now:=save;
    end;

procedure solve;
    var
      i,u,x:longint;
    begin
      for i:=1 to n do
        begin
          f[i]:=1;
          u:=a[i];

          sp:=0;
          for x:=1 to sprime do
            begin
              if prime[x]*prime[x]>u then break;
              if u mod prime[x]=0 then
                begin
                  inc(sp);
                  p[sp]:=prime[x];
                  lt[sp]:=0;
                  while u mod p[sp]=0 do
                    begin
                      u:=u div p[sp];
                      inc(lt[sp]);
                    end;
                end;
            end;
          if u>1 then
            begin
              inc(sp);
              p[sp]:=u;
              lt[sp]:=1;
          end;

          now:=1;
          duyet(1,i);

          pos[a[i]]:=i;
        end;
    end;
procedure ans;
    var
      i,ln,u:longint;
      p:Llist;
    begin
      ln:=0;
      for i:=1 to n do
        begin
          add(a[i],list[f[i]]);
          ln:=max(ln,f[i]);
          inc(size[f[i]]);
        end;
      writeln(f2,ln);
      for i:=1 to ln do
        begin
          write(f2,size[i],' ');
          p:=list[i];
          while p<>nil do
            begin
              u:=p^.u; p:=p^.next;
              write(f2,u,' ');
            end;
          writeln(f2);
        end;
    end;

begin
  openF;
  generate;
  inp;
  sort(1,n);
  solve;
  ans;
  closeF;
end.

Code mẫu của hieult

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
//#include <conio.h>

using namespace std;

int n,a[55555],f[55555],d[1111111],kq = 0;
vector<int> V[10000];

int main(){
   // freopen("NUMBERS.in","r",stdin);
      scanf("%d",&n);
      memset(f,0,sizeof(f));
      memset(d,0,sizeof(d));
      for(int i = 0;i<n;i++) scanf("%d",&a[i]);
      sort(a,a+n);
      for(int i = 0;i<n;i++){
           if(i>0 && a[i]==a[i-1]){
                d[a[i]]++;
                f[i] = f[i-1]+1;
           }
           else{
                 d[a[i]] = 1;
                 if(a[i]!=1)
                       d[a[i]] = max(d[a[i]],d[1]+1);
                 for(int j = 2;j*j<=a[i];j++){
                       if(a[i]%j==0){
                             d[a[i]] = max(d[a[i]],d[j]+1);
                             d[a[i]] = max(d[a[i]],d[a[i]/j]+1);
                       }
                 }
                 f[i] = d[a[i]];
           }
           kq = max(kq,f[i]);
           V[f[i]].push_back(a[i]);
      }
      printf("%d\n",kq);
      //getch();
      for(int i = 1;i<=kq;i++){
            printf("%d ",V[i].size());  
            for(int j = 0;j<V[i].size();j++)
                printf("%d ",V[i][j]);
            printf("\n");
      }
     // getch();
}

Code mẫu của khuc_tuan

#include <iostream>
#include <sstream>
#include <queue>
#include <map>
#include <set>
#include <algorithm>
#include <vector>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <string>
using namespace std;

#define Rep(i,n) for(int i=0;i<(n);++i)
#define For(i,a,b) for(int i=(a);i<=(b);++i)
#define Ford(i,a,b) for(int i=(a);i>=(b);--i)
#define Fit(i,v) for(__typeof(v.begin()) i=v.begin();i!=v.end();++i)
#define Fill(a,b) memset((a), (b), sizeof(a))
#define pb push_back
#define MP make_pair

typedef long long LL;

int n, a[50050], F[50050];
vector<pair<int,int> > ds;
int vt[1000060];

int main() {
    scanf("%d", &n);
    Rep(i,n) scanf("%d", a+i);
    sort( a, a+n);
    Rep(i,n) vt[a[i]] = i+1;
    Rep(i,n) {
        if(i==0) F[i] = 0;
        else if(a[i]==a[i-1]) F[i] = F[i-1]+1;
        else {
            for(int d=1;d*d<=a[i];++d) if(a[i]%d==0) {
                if(vt[d]) F[i] >?= 1 + F[vt[d]-1];
                if(d!=1 && vt[a[i]/d]) F[i] >?= 1 + F[vt[a[i]/d]-1];
            }
        }
        ds.pb(MP(F[i],a[i]));
    }
    int res = 0;
    Rep(i,n) res >?= F[i]; 
    printf("%d\n", res+1);
    sort( ds.begin(), ds.end());
    int last = 0;
    Rep(i,ds.size()+1) {
        if(i==ds.size() || (i!=0 && ds[i].first!=ds[i-1].first)) {
            printf("%d", i - last);
            For(j,last,i-1) printf(" %d", ds[j].second);
            printf("\n");
            last = i;
        }
    }
    //system("pause");
    return 0;
}