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

Code mẫu của RR

//Written by RR

{$MODE OBJFPC}

uses math;
const
  FINP          =       '';
  FOUT          =       '';
  MAXN          =       10111;

type
  st            =       string[101];

var
  f1,f2         :       text;
  n,k           :       longint;
  a             :       array[1..2,1..MAXN] of st;

procedure openF;
    begin
      assign(f1,FINP); reset(f1);
      assign(f2,FOUT); rewrite(f2);
    end;

procedure closeF;
    begin
      close(f1);
      close(f2);
    end;

var
  s             :       string;

procedure inp;
    var
      i,j:longint;
      c:char;
    begin
      readln(f1,n,k);
      for i:=1 to n do
        begin
          readln(f1,s);
          a[1,i]:=copy(s,1,k);
          for j:=k downto 1 do
            a[2,i]:=a[2,i]+s[k+j];
        end;
    end;

procedure swap(var a,b:st); inline;
    var
      tmp:st;
    begin
      tmp:=a; a:=b; b:=tmp;
    end;

procedure sort(x,l,r:longint); inline;
    var
      i,j:longint;
      mid:st;
    begin
      i:=l; j:=r; mid:=a[x,l+random(r-l+1)];
      repeat
        while (a[x,i]<mid) do inc(i);
        while (a[x,j]>mid) do dec(j);
        if i<=j then
          begin
            swap(a[x,i],a[x,j]);
            inc(i); dec(j);
          end;
      until i>j;
      if i<r then sort(x,i,r);
      if l<j then sort(x,l,j);
    end;

procedure solve;
    var
      now,i,j,res:longint;
    begin
      res:=0;
      for now:=1 to 2 do
        begin
          sort(now,1,n);
          inc(res,k);
          for i:=2 to n do
            begin
              j:=1;
              while (j<=k) and (a[now,i,j]=a[now,i-1,j]) do inc(j);
              inc(res,k-j+1);
            end;
        end;
      writeln(f2,res);
    end;

begin
  openF;
  inp;
  solve;
  closeF;
end.

Code mẫu của hieult

#include<cstdio>
#include<cmath>
#include<cstring>
#include<cstdlib>
#include<cassert>
#include<ctime>
#include<algorithm>
#include<iterator>
#include<iostream>
#include<cctype>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<list>
//#include<conio.h>
#define ep 0.000000001
#define maxn 10011
#define oo 1111111111
#define base 100000000
#define TR(c, it) for(typeof((c).begin()) it=(c).begin(); it!=(c).end(); it++)
double const PI=4*atan(1);

using namespace std;

typedef pair<int, int> II;
typedef vector<int> VI;
typedef vector<II> VII;
typedef vector<VI> VVI;
typedef vector<VII> VVII;

int n,k;

int xuly(vector<string> a){
     sort(a.begin(),a.end());
     int kq = k,j;
     for(int i = 1;i<n;i++){
           for(j = 0; j<k;j++)
                if(a[i][j]!=a[i-1][j])
                      break;
           kq+=k-j;
     }
     return kq;
}

vector<string> u,v;
string a,b;
char s[222];

int main(){
     //freopen("KOKOS.in","r",stdin);
     scanf("%d %d",&n,&k);
     for(int i = 0;i<n;i++){
           scanf("%s",s);
           a = s;
           b = s;
           reverse(b.begin(),b.end());
           a.resize(k);
           b.resize(k);
           u.push_back(a);
           v.push_back(b);
     }
     printf("%d",xuly(u)+xuly(v));
    // getch();
}

Code mẫu của ll931110

{$mode delphi}
program MKOKOS;
const
  input  = '';
  output = '';
  maxn = 10000;
var
  n,k,res: integer;
  s: array[1..maxn] of string;
  a: array[1..maxn] of string;

procedure init;
var
  f: text;
  i: integer;
begin
  assign(f, input);
    reset(f);

  readln(f, n, k);
  for i := 1 to n do readln(f, s[i]);

  close(f);
end;

procedure swap(var x,y: string);
var
  z: string;
begin
  z := x;  x := y;  y := z;
end;

procedure quicksort;

  procedure par(l,h: integer);
  var
    i,j: integer;
    p: string;
  begin
    if l >= h then exit;
    i := l;  j := h;  p := a[random(h - l + 1) + l];

    repeat
      while a[i] < p do inc(i);
      while p < a[j] do dec(j);

      if i <= j then
        begin
          if i < j then swap(a[i],a[j]);
          inc(i);
          dec(j);
        end;
    until i > j;

    par(l,j);
    par(i,h);
  end;

begin
  par(1,n);
end;

procedure solve;
var
  i,j,c: integer;
begin
  res := 0;
  for i := 1 to n do a[i] := copy(s[i],1,k);
  quicksort;

  res := res + k;
  for i := 2 to n do
    begin
      c := 1;
      while (c <= k) and (a[i][c] = a[i - 1][c]) do inc(c);
      res := res + (k + 1 - c);
    end;

  for i := 1 to n do
    for j := 1 to k do a[i][j] := s[i][2 * k + 1 - j];
  quicksort;

  res := res + k;
  for i := 2 to n do
    begin
      c := 1;
      while (c <= k) and (a[i][c] = a[i - 1][c]) do inc(c);
      res := res + (k + 1 - c);
    end;

end;

procedure printresult;
var
  f: text;
begin
  assign(f, output);
    rewrite(f);
    writeln(f, res);
  close(f);
end;

begin
  init;
  solve;
  printresult;
end.