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

{$R+,Q+}
uses math;
const
  FINP='';
  FOUT='';
  MAXN=100001;
var
  f1,f2:text;
  g,n,test:longint;
  a:array[1..MAXN] of char;
procedure openF;
begin
  assign(f1,FINP); reset(f1);
  assign(f2,FOUT); rewrite(f2);
end;
procedure closeF;
begin
  close(f1); close(f2);
end;
procedure inp;
begin
  readln(f1,n);
  fillchar(a,sizeof(a),'0');
  for n:=1 to n do read(f1,a[n]);
  readln(f1);
end;
procedure solve;
var
  l,i,u:longint;
  last:char;
begin
  l:=0;
  for i:=1 to n do
    begin
      if a[i]<>'0' then
        begin
          last:=a[i];
          break;
        end;
      inc(l);
    end;
  if l=n then begin g:=2-n mod 2; exit; end;
  g:=l; l:=0;
  for u:=i+1 to n do
    begin
      if a[u]<>'0' then
        begin
          if (last=a[u]) and (l>0) then g:=g xor 1;
          if (last<>a[u]) and (l>0) then g:=g xor 0;
          last:=a[u]; l:=0;
        end
      else inc(l);
    end;
  g:=g xor l;
end;
procedure ans;
begin
  if g=0 then writeln(f2,2) else writeln(f2,1);
end;
begin
  openF;
  readln(f1,test);
  for test:=1 to test do
    begin
      inp;
      if n=0 then begin writeln(f2,2); continue; end;
      solve;
      ans;
    end;
  closeF;
end.

Code mẫu của hieult

#include <stdio.h>
//#include <conio.h>

int TTD(int a)
{
    if(a<0)
       return -a;
    else return a;
}

int main()
{
    int test,n;
    char s[100001];
    scanf("%d",&test);
    for(int ii = 1;ii<=test;ii++)
    {
        scanf("%d",&n);
        scanf("%s",s);
        int trai = 0,phai = 0,tong = 0,thutu=0,flag = 0;
        for(int i = 0;i<n;i++)
        {
            if(flag == 0)
            {
                if(s[i]=='0')
                    trai++;
                else 
                {
                    flag = 1;
                    thutu = i;
                }
            }
            else if(s[i]!='0')
            {
                if(i-thutu>1 && s[i]==s[thutu])
                    tong++;
                thutu=i;
            }
            else if(i==n-1)
                phai = n-1-thutu;
        }
        if(trai==phai)
        {
            if(tong%2==0) printf("2\n");
            else printf("1\n");
        }
        else if(TTD(trai-phai)==1)
        {
            if(trai%2==0)
            {
                if(trai<phai)
                {
                    if(tong%2==0) printf("1\n");
                    else printf("2\n");
                }
                else printf("1\n");
            }
            else
            {
                if(trai>phai)
                {
                    if(tong%2==0) printf("1\n");
                    else printf("2\n");
                }
                else printf("1\n");
            }
        }
        else printf("1\n");
    }
    //getch();
}

Code mẫu của ll931110

program BWGAME;
const
  input  = '';
  output = '';
  maxn = 100000;
var
  fi,fo: text;
  i,nTest: longint;
  a: array[1..maxn] of longint;
  gr: array[0..maxn,0..2,0..2] of longint;

procedure openfile;
begin
  assign(fi, input);  reset(fi);
  assign(fo, output);  rewrite(fo);
end;

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

procedure gens;
var
  i: longint;
begin
  fillchar(gr, sizeof(gr), 0);
  for i := 1 to maxn do
    begin
     gr[i,0,1] := i;  gr[i,0,2] := i;  gr[i,1,0] := i;  gr[i,2,0] := i;
     gr[i,1,1] := 1;  gr[i,2,2] := 1;
     if odd(i) then gr[i,0,0] := 1;
    end;
end;

procedure solve;
var
  n,i: longint;
  cc,xa,xb,res: longint;
  ch: char;
begin
  readln(fi, n);
  for i := 1 to n do
    begin
      read(fi, ch);
      a[i] := ord(ch) - ord('0');
    end;

  readln(fi);

  res := 0;
  xa := 0;
  xb := 0;

  i := 1;
  while i <= n do
    begin
      cc := 0;
      while (i <= n) and (a[i] = 0) do
        begin
          inc(i);  inc(cc);
        end;

      if i <= n then xb := a[i];
      res := res xor gr[cc,xa,xb];

      xa := xb;
      xb := 0;
      cc := 0;
      inc(i);
    end;

  if res = 0 then writeln(fo, 2) else writeln(fo, 1);
end;

begin
  openfile;
  gens;

  readln(fi, nTest);
  for i := 1 to nTest do solve;

  closefile;
end.

Code mẫu của khuc_tuan

#include "stdio.h"
#include "string.h"
#include "queue"

using namespace std;

char s[100010];
int n;

int main() {
    int stest;
    scanf("%d",&stest);
    while(stest--) {
        scanf("%d",&n);
        gets(s); gets(s);
        int res = 0 ;
        for(int i=0;i<n;++i) if(s[i]=='0'){
            int j = i;
            while(j+1<n && s[j+1]=='0') ++j;
            int len = j-i+1;
            int a,b;
            if(i==0) a=0; else a='3'-s[i-1];
            if(j==n-1) b=0; else b='3'-s[j+1];

            if(a==b) {
                if(b!=0 || len%2==1) res ^= 1; 
            }
            else if(a==0 || b==0) res ^= len;

            i = j;
        }
        if(res==0) printf("2\n");
        else printf("1\n");
    }
    return 0;
}