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

Code mẫu của flashmt

uses math;
var a:ansistring;
    n,i,j,l,t,r:longint;
    re:boolean;
    f:array[0..1000100] of longint;

begin
     readln(t);
     while t>0 do
     begin
          dec(t);
          readln(a);
          n:=length(a);
          if n=0 then re:=true
          else
          begin
               r:=0; l:=1;
               for i:=1 to n do
               begin
                    if i>r then j:=1
                    else j:=min(f[l+r-i+1],r-i+1)+1;
                    while (i+j-1<=n) and (i-j>0) and (a[i+j-1]=a[i-j]) do inc(j);
                    dec(j);
                    f[i]:=j;
                    if i+j-1>r then
                    begin
                         l:=i-j; r:=i+j-1;
                    end;
               end;
               r:=1; i:=1;
               while i<=n do
               begin
                    if (f[i]>0) and (i-f[i]<=r) then
                    begin
                         r:=i+f[i]; i:=r;
                    end
                    else inc(i);
               end;
               re:=r>n;
          end;
          if re then writeln('YES')
          else writeln('NO');
     end;
end.

Code mẫu của ladpro98

#include <cstring>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <climits>
#include <cstdlib>
#include <ctime>
#include <memory.h>
#include <cassert>
#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 TR(it, a) for(typeof((a).begin()) it = (a).begin(); it != (a).end(); ++it)
#define RESET(a, v) memset((a), (v), sizeof((a)))
#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 = 1000015;
using namespace std;

string s;
int POW[N], h[N], rh[N];
int n;

int getHash(int l, int r) {
    return h[r] - h[l - 1] * POW[r - l + 1];
}

int getRHash(int l, int r) {
    return rh[l] - rh[r + 1] * POW[r - l + 1];
}

bool isPalin(int l, int r) {
    int mid = l + r >> 1;
    return getHash(l, mid) == getRHash(mid + 1, r);
}

int main() {
    ios :: sync_with_stdio(0); cin.tie(0);
    POW[0] = 1;
    FOR(i, 1, N) POW[i] = POW[i - 1] * 135;
    int nTest;
    cin >> nTest;
    getline(cin, s);
    while (nTest--) {
        getline(cin, s);
        if (s[s.size()-1] == '\r') s.erase(s.size()-1);
        n = SZ(s);
        s = '#' + s;
        REP(i, 1, n) h[i] = h[i - 1] * 135 + s[i];
        rh[n + 1] = 0;
        REPD(i, n, 1) rh[i] = rh[i + 1] * 135 + s[i];
        int l = 1;
        for(int r = 2; r <= n; r += 2)
            if (isPalin(l, r)) l = r + 1;
        cout << (l > n ? "YES\n" : "NO\n");
    }
    return 0;
}

Code mẫu của RR

//Written by RR

{$MODE OBJFPC}
{$R-,Q-}

uses math;
const
  FINP          =       '';
  FOUT          =       '';
  MAXN          =       1000111;
  hkey          =       2147483647;

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

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

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

procedure inp;
    var
      c:char;
    begin
      n:=0;
      while not seekeoln(f1) do
        begin
          inc(n);
          read(f1,c);
          a[n]:=ord(c);
        end;
      readln(f1);
    end;

function check:boolean;
    var
      i,j:longint;
      r1,r2,lt:longint;
      ok:boolean;
    begin
      i:=1; j:=1;
      repeat
        ok:=false; r1:=a[i]; r2:=a[i]; j:=i; lt:=1;
        while (j<n) do
          begin
            inc(j);
            r1:=(r1 shl 8+a[j]) and hkey;
            lt:=(lt shl 8) and hkey;
            r2:=(r2+a[j]*lt) and hkey;
            if ((j-i) and 1=1) and (r1=r2) then
              begin
                ok:=true;
                i:=j+1;
                break;
              end;
          end;
        if not ok then exit(false);
      until i>n;
      exit(true);
    end;

begin
  openF;
  readln(f1,test);
  for test:=1 to test do
    begin
      inp;
      if n=0 then writeln(f2,'YES')
      else if n and 1=1 then writeln(f2,'NO')
      else if check then writeln(f2,'YES')
      else writeln(f2,'NO');
    end;
  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 1000011
#define oo 1000000000
#define ooo 1ll << 62
#define mod 111539786
#define TR(c, it) for(typeof((c).begin()) it=(c).begin(); it!=(c).end(); it++)
#define fi first 
#define se second
#define max_size 4
double const PI=4*atan(1);

typedef long long int64;

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 f[maxn], n, test;
char s[maxn];

void manacher(char s[]){
    int l = 0, r = -1;
    memset(f, 0, sizeof(f));
    for(int i = 0; i < n; i++){
        int k = (i > r ? 0 : min(f[l + r - i + 1], r - i + 1)) + 1;
        while(i + k - 1 < n && i - k >= 0 && s[i + k - 1] == s[i - k]) k ++;
        f[i] = --k;
        if(i + k - 1 > r)
            r = i + k - 1, l = i - k;
        //printf("%d ",f[i]);
    }
}

int main(){

   // freopen("input.in","r",stdin); 
   // freopen("output.out","w",stdout);
    scanf("%d",&test);
    gets(s);
    while(test--){
        gets(s);
        n = strlen(s);
        if(s[n - 1] == '\r') n--;
        manacher(s);
        int u = n - 1;
        for(int i = n - 1; i >= 0; i--) if(i + f[i] > u) u <?= i - f[i] - 1;
        if( u < 0) printf("YES\n");
        else printf("NO\n");
    }
   // getch();
}

Code mẫu của ll931110

program paldr;
uses math;
const
  input  = '';
  output = '';
  maxn = 1000000;
var
  fi,fo: text;
  rad: array[0..maxn] of longint;
  a: array[0..maxn] of char;
  s: ansistring;
  n: longint;
  i,nTest: longint;

procedure openfile;
begin
  assign(fi, input);
    reset(fi);

  assign(fo, output);
    rewrite(fo);
end;

procedure solve;
var
  i,j,k: longint;
  st,cur: longint;
begin
  readln(fi, s);
  n := length(s);
  for i := 0 to n - 1 do a[i] := s[i + 1];

  if n = 1 then
    begin
      writeln(fo, 'NO');
      exit;
    end;

  i := 0;
  j := 0;
  while i < n do
    begin
      while (i >= j) and (i + 1 + j < n) and (a[i - j] = a[i + 1 + j]) do inc(j);
      rad[i] := j;

      k := 1;
      while (i >= k) and (i + k < n) and (k <= rad[i]) and (rad[i - k] <> rad[i] - k) do
        begin
          rad[i + k] := min(rad[i - k],rad[i] - k);
          inc(k);
        end;

      j := max(j - k,0);
      i := i + k;
    end;

  st := 0;
  cur := 2;
  while cur <= n do
    begin
      if rad[(cur + st) div 2 - 1] * 2 >= cur - st then st := cur;
      cur := cur + 2;
    end;

  if st = n then writeln(fo, 'YES') else writeln(fo, 'NO');
end;

procedure closefile;
begin
  close(fo);
  close(fi);
end;

begin
  openfile;
  readln(fi, nTest);
  for i := 1 to nTest do solve;
  closefile;
end.