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

const fi='';
      fo='';
      maxn=512;
      maxc=1000000000;
      dx:array[1..4] of longint=(-1,-1,0,0);
      dy:array[1..4] of longint=(-1,0,-1,0);
var n,m:longint;
    a,re:array[1..maxn,1..maxn] of byte;
    min,b,tr:array[0..9,1..maxn,1..maxn] of longint;
    p:array[0..9] of longint;
    d:array[1..4] of byte;
    dt:array[1..9,1..maxn div 2,1..maxn div 2,1..4] of byte;

procedure rf;
var i,j:longint; c:char;
begin
     assign(input,fi);
     reset(input);
     readln(n);
     for i:=1 to n do
     begin
          for j:=1 to n do
          begin
               read(c);
               if c='0' then
               begin
                    a[i,j]:=0;
                    b[0,i,j]:=0;
               end
               else
               begin
                    a[i,j]:=1;
                    b[0,i,j]:=1;
               end;
          end;
          readln;
     end;
     re:=a;
     p[0]:=1;
     for i:=1 to 9 do p[i]:=p[i-1] shl 1;
     close(input);
end;

procedure fill2(deg,x,y,val:longint);
var i,j:longint;
begin
     for i:=p[deg]*(x-1)+1 to p[deg]*x do
         for j:=p[deg]*(y-1)+1 to p[deg]*y do
             re[i,j]:=val;
end;

procedure fill(deg,x,y:longint);
var i,j,p,q:longint;
begin
     p:=tr[deg,x,y] div 10; q:=tr[deg,x,y] mod 10;
     fill2(deg-1,2*x+dx[p],2*y+dy[p],0);
     fill2(deg-1,2*x+dx[q],2*y+dy[q],1);
     if deg=1 then exit;
     dt[deg,x,y,p]:=1; dt[deg,x,y,q]:=1;
     for i:=1 to 4 do
         if dt[deg,x,y,i]=0 then fill(deg-1,2*x+dx[i],2*y+dy[i]);
end;

procedure pr;
var i,j,k,t,r,q,s,u:longint; kt:boolean;
begin
     for i:=1 to 9 do
     begin
          t:=n div p[i];
          if t=0 then break;
          for j:=1 to t do
              for k:=1 to t do
              begin
                   min[i,j,k]:=maxc;
                   r:=2*j; q:=2*k;
                   b[i,j,k]:=b[i-1,r-1,q-1]+b[i-1,r-1,q]+b[i-1,r,q-1]+b[i-1,r,q];
              end;
     end;
     m:=i-1;
     if n=512 then m:=9;
     for i:=1 to m do
     begin
       t:=n div p[i];
       for j:=1 to t do
         for k:=1 to t do
         begin
              kt:=false;
              for r:=1 to 4 do
                if kt then break
                else
                for q:=1 to 4 do
                  if r<>q then
                  begin
                       fillchar(d,sizeof(d),0);
                       d[r]:=1; d[q]:=1;
                       s:=b[i-1,2*j+dx[r],2*k+dy[r]]+p[i-1]*p[i-1]-b[i-1,2*j+dx[q],2*k+dy[q]];
                       for u:=1 to 4 do
                           if d[u]=0 then
                              s:=s+min[i-1,2*j+dx[u],2*k+dy[u]];
                       if s<min[i,j,k] then
                       begin
                            min[i,j,k]:=s;
                            kt:=s=0;
                            tr[i,j,k]:=r*10+q;
                            if kt then break;
                       end;
                  end;
         end;
     end;
     fill(m,1,1);
end;

procedure wf;
var i,j:longint;
begin
     assign(output,fo);
     rewrite(output);
     writeln(min[m,1,1]);
     for i:=1 to n do
     begin
          for j:=1 to n do
              write(re[i,j]);
          writeln;
     end;
     close(output);
end;

begin
     rf;
     pr;
     wf;
end.

Code mẫu của ladpro98

{$H+}
program slikar;
uses    math;
const   maxn=513;
        maxP = 10;
        oo=trunc(1e9);
        fi='';
        b = 1;//black;
        w = 0;//white;
        r = 2;//recursive;
var     f:array[1..maxn,1..maxn,0..maxP,0..2] of longint;
        //F[i,j,k,t] = Chenh lech min cua hinh vuong goc duoi phai la i,j, canh = 2^k, to theo cach t;
        check:array[1..maxn,1..maxn,0..maxP,0..2] of boolean;
        trace:array[1..maxn,1..maxn,0..maxP] of longint;
        res:array[1..maxn,1..maxn] of longint;
        a:array[1..maxn] of string;
        pow:array[0..10] of longint;
        per:array[0..30,0..4] of longint;
        n,pn,d:longint;

procedure input;
var     inp:text;
        i:longint;
begin
        assign(inp,fi);reset(inp);
        readln(inp,n);
        for i:=1 to n do readln(inp,a[i]);
        close(inp);
        pow[0]:=1;
        for i:=1 to 10 do pow[i]:=2*pow[i-1];
        for i:=0 to 10 do if pow[i] = n then pn:=i;
end;

procedure GenPer;
var     i,k,j,t:longint;
begin
        for i:=1 to 3 do
        for j:=i+1 to 4 do
        for t:=0 to 1 do
        begin
                inc(d);
                per[d,i]:=2;per[d,j]:=2;
                for k:=1 to 4 do
                if (k<>i) and (k<>j) then
                begin
                        per[d,k]:=t;
                        break;
                end;
                for k:=4 downto 1 do
                if (k<>i) and (k<>j) then
                begin
                        per[d,k]:=1-t;
                        break;
                end;
        end;
end;

function dp(i,j,k,t:longint):longint;
var     i1,i2,i3,j1,j2,j3,x,temp:longint;
begin
        if check[i,j,k,t] then exit(f[i,j,k,t]);
        check[i,j,k,t]:=true;
        if k=0 then
        begin
                if (t=2) or (a[i][j] = chr(t+48)) then f[i,j,k,t]:=0
                else    f[i,j,k,t]:=1;
                exit(f[i,j,k,t]);
        end;
        i1:=(i+i-pow[k]) shr 1; j1:=(j+j-pow[k]) shr 1;
        i2:=i1;j2:=j;
        i3:=i; j3:=j1;
        if (t<2) then
        f[i,j,k,t]:=dp(i1,j1,k-1,t)+dp(i2,j2,k-1,t)+dp(i3,j3,k-1,t)+dp(i,j,k-1,t)
        else
        begin
                f[i,j,k,t]:=oo;
                for x:=1 to d do
                begin
                        temp:=
                        dp(i1,j1,k-1,per[x,1])+dp(i2,j2,k-1,per[x,2])+
                        dp(i3,j3,k-1,per[x,3])+dp(i,j,k-1,per[x,4]);
                        if f[i,j,k,t]>temp then
                        begin
                                f[i,j,k,t]:=temp;
                                trace[i,j,k]:=x;
                        end;
                end;
        end;
        exit(f[i,j,k,t]);
end;

procedure print(i,j,k,t:longint);
var     p,q,i1,i2,i3,j1,j2,j3:longint;
begin
        if (t<2) then
        begin
                for p:=i-pow[k]+1 to i do
                for q:=j-pow[k]+1 to j do
                res[p,q]:=t;
                exit;
        end;
        if k=0 then
        begin
                res[i,j]:=ord(a[i][j])-48;
                exit;
        end;
        i1:=(i+i-pow[k]) shr 1; j1:=(j+j-pow[k]) shr 1;
        i2:=i1;j2:=j;
        i3:=i; j3:=j1;
        print(i1,j1,k-1,per[trace[i,j,k],1]);
        print(i2,j2,k-1,per[trace[i,j,k],2]);
        print(i3,j3,k-1,per[trace[i,j,k],3]);
        print(i,j,k-1,per[trace[i,j,k],4]);
end;

procedure process;
var     i,j:longint;
begin
        writeln(dp(n,n,pn,r));
        print(n,n,pn,r);
        for i:=1 to n do
        begin
                for j:=1 to n do write(res[i,j]);
                writeln;
        end;
end;

begin
        input;
        GenPer;
        process;
end.

Code mẫu của RR

{$R+,Q+}
uses math;
const
  FINP='';
  FOUT='';
  MAXN=512;
  snode=400000;
var
  f1,f2:text;
  vt0,vt1,vtx,vty,vt,n:longint;
//  timeold:longint;
  kq,a:array[1..MAXN,1..MAXN] of longint;
  color,diff1,diff0,diff,s0,s1:array[1..snode] 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
  i,j:longint;
  ch:char;
begin
  readln(f1,n);
  for i:=1 to n do
    begin
      for j:=1 to n do
        begin
          read(f1,ch);
          if ch='0' then a[i,j]:=0 else a[i,j]:=1;
        end;
      readln(f1);
    end;
end;
procedure build(i,u1,u2,v1,v2:longint);
var
  mu,mv:longint;
begin
  if (u1=u2) then
    begin
      if a[u1,v1]=0 then
        begin
          s0[i]:=1; s1[i]:=0;
          diff0[i]:=0; diff1[i]:=1;
          diff[i]:=0;
        end
      else //a[u1,v1]=1
        begin
          s0[i]:=0; s1[i]:=1;
          diff0[i]:=1; diff1[i]:=0;
          diff[i]:=0;
        end;
      exit;
    end;
  mu:=(u1+u2)>>1; mv:=(v1+v2)>>1;
  build(i<<2-2,u1,  mu,v1,mv); build(i<<2-1,u1,  mu,mv+1,v2);
  build(i<<2  ,mu+1,u2,v1,mv); build(i<<2+1,mu+1,u2,mv+1,v2);
  s0[i]:=s0[i<<2-2]+s0[i<<2-1]+s0[i<<2]+s0[i<<2+1];
  s1[i]:=s1[i<<2-2]+s1[i<<2-1]+s1[i<<2]+s1[i<<2+1];
  diff0[i]:=s1[i]; diff1[i]:=s0[i];
  diff[i]:=maxlongint;
  for vt0:=i<<2-2 to i<<2+1 do
  for vt1:=i<<2-2 to i<<2+1 do
  if vt0<>vt1 then
    begin
      vtx:=0; vty:=0;
      for vt:=i<<2-2 to i<<2+1 do
        if (vt<>vt0) and (vt<>vt1) then
          if vtx=0 then vtx:=vt else vty:=vt;
      diff[i]:=min(diff[i],diff0[vt0]+diff1[vt1]+diff[vtx]+diff[vty]);
    end;
end;
var
  i,j:longint;
procedure cal(i,u1,u2,v1,v2,k:longint);
var
  mu,mv:longint;
begin
  if k=0 then exit;
  if k=1 then
  begin
    for i:=u1 to u2 do
    for j:=v1 to v2 do
      kq[i,j]:=k;
    exit;
  end;
  if u1=u2 then
    begin
      kq[u1,v1]:=a[u1,v1];
      exit;
    end;
  mu:=(u1+u2)>>1; mv:=(v1+v2)>>1;
  for vt0:=i<<2-2 to i<<2+1 do
  for vt1:=i<<2-2 to i<<2+1 do
  if vt0<>vt1 then
    begin
      vtx:=0; vty:=0;
      for vt:=i<<2-2 to i<<2+1 do
        if (vt<>vt0) and (vt<>vt1) then
          if vtx=0 then vtx:=vt else vty:=vt;
      if diff[i]=diff0[vt0]+diff1[vt1]+diff[vtx]+diff[vty] then
        begin
          color[vt0]:=0; color[vt1]:=1; color[vtx]:=2; color[vty]:=2;
          cal(i<<2-2,u1,  mu,v1,  mv,color[i<<2-2]);
          cal(i<<2-1,u1,  mu,mv+1,v2,color[i<<2-1]);
          cal(i<<2  ,mu+1,u2,v1,  mv,color[i<<2  ]);
          cal(i<<2+1,mu+1,u2,mv+1,v2,color[i<<2+1]);
          exit;
        end;
    end;
end;
procedure ans;
begin
  writeln(f2,diff[1]);
  for i:=1 to n do
    begin
      for j:=1 to n do write(f2,kq[i,j]);
      writeln(f2);
    end;
end;
begin
//  timeold:=getTickCount;
  openF;
  inp;
  build(1,1,n,1,n);
  cal(1,1,n,1,n,2);
  ans;
  closeF;
//  writeln(getTickCount-timeold);
end.

Code mẫu của hieult

#include <set>
#include <map>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <bitset>
#include <cctype>
#include <cstdio>
#include <string>
#include <vector>
#include <cassert>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <iomanip>
#include <iostream>
#include <algorithm>

using namespace std;

typedef long long ll;
typedef long double ld;
//typedef double ld;
typedef unsigned int ui;
typedef unsigned long long ull;

#define Rep(i,n) for(__typeof(n) i = 0; i < (n); ++i)
#define Repd(i,n) for(__typeof(n) i = (n)-1; i >= 0; --i)
#define For(i,a,b) for(__typeof(b) i = (a); i <= (b); ++i)
#define Ford(i,a,b) for(__typeof(a) i = (a); i >= (b); --i)
#define Fit(i,v) for(__typeof((v).begin()) i = (v).begin(); i != (v).end(); ++i)
#define Fitd(i,v) for(__typeof((v).rbegin()) i = (v).rbegin(); i != (v).rend(); ++i)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define sz(a) ((int)(a).size())
#define all(a) (a).begin(), (a).end()
#define ms(a,x) memset(a, x, sizeof(a))
#define nl puts("")
#define sp printf(" ")
#define ok puts("ok")
//#include <conio.h>

template<class F, class T> T convert(F a, int p = -1) { stringstream ss; if (p >= 0) ss << fixed << setprecision(p); ss << a; T r; ss >> r; return r; }
template<class T> void db(T a, int p = -1) { if (p >= 0) cout << fixed << setprecision(p); cout << a << " "; }
template<class T> T gcd(T a, T b) { T r; while (b != 0) { r = a % b; a = b; b = r; } return a; }
template<class T> T lcm(T a, T b) { return a / gcd(a, b) * b; }
template<class T> T sqr(T x) { return x * x; }
template<class T> T cube(T x) { return x * x * x; }
template<class T> struct Triple { T x, y, z; Triple() {} Triple(T _x, T _y, T _z) : x(_x), y(_y), z(_z) {} };
template<class T> Triple<T> euclid(T a, T b) { if (b == 0) return Triple<T>(1, 0, a); Triple<T> r = euclid(b, a % b); return Triple<T>(r.y, r.x - a / b * r.y, r.z); }
template<class T> int getbit(T s, int i) { return (s >> i) & 1; }
template<class T> T onbit(T s, int i) { return s | (T(1) << i); }
template<class T> T offbit(T s, int i) { return s & (~(T(1) << i)); }
template<class T> int cntbit(T s) { return s == 0 ? 0 : cntbit(s >> 1) + (s & 1); }
const int bfsz = 1 << 16; char bf[bfsz + 5]; int rsz = 0;int ptr = 0;
char gc() { if (rsz <= 0) { ptr = 0; rsz = fread(bf, 1, bfsz, stdin); if (rsz <= 0) return EOF; } --rsz; return bf[ptr++]; }
void ga(char &c) { c = EOF; while (!isalpha(c)) c = gc(); }
int gs(char s[]) { int l = 0; char c = gc(); while (isspace(c)) c = gc(); while (c != EOF && !isspace(c)) { s[l++] = c; c = gc(); } s[l] = '\0'; return l; }
template<class T> bool gi(T &v) {
    v = 0; char c = gc(); while (c != EOF && c != '-' && !isdigit(c)) c = gc(); if (c == EOF) return false; bool neg = c == '-'; if (neg) c = gc();
    while (isdigit(c)) { v = v * 10 + c - '0'; c = gc(); } if (neg) v = -v; return true;
}

const double PI = 2 * acos(0);
const string months[] = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};
const int days[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
const int dr[] = {-1, +0, +1, +0};
const int dc[] = {+0, +1, +0, -1};
const int inf = (int)1e9 + 5;
const ll linf = (ll)1e16 + 5;
const ld eps = ld(1e-9);
const ll mod = 100000007;
typedef pair<int, int> II;

#define maxn 515

int n, m;
string s[maxn], res[maxn];
int a[maxn][maxn][11], f[maxn][maxn][11], d[maxn][maxn][11][2];

int cal2(int x){
    if(x == 1) return 0;
    return 1 + cal2(x >> 1);
}

int B(int x){
    return 1 << x;
}

void Boi(int r, int c, int id, int mau){
    For(i, r, r + B(id) - 1) For(j, c, c + B(id) - 1)
        res[i][j] = mau + '0';
}

void paint(int r, int c, int id){
    if(id == 0){
        res[r][c] = s[r][c];
        return;
    }
    int i = d[r][c][id][0];
    int j = d[r][c][id][1];
    int t1 = -1, t2;
    Rep(k, 4) if(k != i && k!= j){
        if(t1 == -1) t1 = k;
        else t2 = k;
    }
    Boi(r + (i >> 1) * B(id - 1), c + (i & 1) * B(id - 1), id - 1, 0);
    Boi(r + (j >> 1) * B(id - 1), c + (j & 1) * B(id - 1), id - 1, 1);
    paint(r + (t1 >> 1) * B(id - 1), c + (t1 & 1) * B(id - 1), id - 1);
    paint(r + (t2 >> 1) * B(id - 1), c + (t2 & 1) * B(id - 1), id - 1);
}

void go(int r, int c, int id){
    if(id == 0) {f[r][c][id] = 0; return;}
    go(r, c, id - 1);
    go(r, c + B(id - 1), id - 1);
    go(r + B(id - 1), c, id - 1);
    go(r + B(id - 1), c + B(id - 1), id - 1);
    int &res = f[r][c][id];
    res = inf;
    Rep(i, 4) Rep(j, 4) if(i != j){
        int t, t1 = -1, t2;
        Rep(k, 4) if(k != i && k!= j){
            if(t1 == -1) t1 = k;
            else t2 = k;
        }
        t = a[r + (i >> 1) * B(id - 1)][c + (i & 1) * B(id - 1)][id - 1]
        + B(id + id - 2) - a[r + (j >> 1) * B(id - 1)][c + (j & 1) * B(id - 1)][id - 1]
        + f[r + (t1 >> 1) * B(id - 1)][c + (t1 & 1) * B(id - 1)][id - 1]
        + f[r + (t2 >> 1) * B(id - 1)][c + (t2 & 1) * B(id - 1)][id - 1];
        if(t < res){
            res = t;
            d[r][c][id][0] = i;
            d[r][c][id][1] = j;
        }
    }
   // if(r == 0 && c == 0 && id == m) cout << res << endl;
}

int main(){
//    freopen("in.txt", "r", stdin);
//    freopen("out.txt", "w", stdout);
    cin >> n;
    Rep(i, n) cin >> s[i];
    Rep(i, n) Rep(j, n) a[i][j][0] = s[i][j] - '0';
    m = cal2(n);
    Rep(i, n) res[i].resize(n);
    For(i, 1, m){
        For(r, 0, n - (1 << i))
            For(c, 0, n - (1 << i)){
                a[r][c][i] = a[r][c][i - 1] + a[r + B(i - 1)][c][i - 1]
                            +a[r][c + B(i - 1)][i - 1] + a[r + B(i - 1)][c + B(i - 1)][i - 1];
            }
    }
    go(0, 0, m);
    paint(0, 0, m);
    printf("%d\n", f[0][0][m]);
    Rep(i, n) cout << res[i] << endl;
}

Code mẫu của ll931110

#include <algorithm>
#include <bitset>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <deque>
#include <fstream>
#include <iostream>
#include <iterator>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <string>
#include <vector>
typedef long long ll;
using namespace std;

int mx[4] = {0,0,1,1};
int my[4] = {0,1,0,1};
int n;
int a[520][520],b[520][520],fin[520][520];
int f[520][520][11],p0[520][520][11],p1[520][520][11];

int get(int x1,int y1,int x2,int y2)
{
    return b[x2][y2] - b[x1 - 1][y2] - b[x2][y1 - 1] + b[x1 - 1][y1 - 1];
};

int rec(int x,int y,int k)
{
    if (f[x][y][k] != -1) return f[x][y][k];
    if (!k)
    {
       f[x][y][k] = 0;  return 0;
    };

    int best = 1000000000,len = 1 << (k - 1);
    for (int i = 0; i < 4; i++)
      for (int j = 0; j < 4; j++) if (i != j)
      {
          int tmp = get(x + len * mx[i],y + len * my[i],x - 1 + len * mx[i] + len,y - 1 + len * my[i] + len);  //color with 0
          tmp += len * len - get(x + len * mx[j],y + len * my[j],x - 1 + len * mx[j] + len,y - 1 + len * my[j] + len);  //color with 1
          for (int t = 0; t < 4; t++) if (t != i && t != j)
            tmp += rec(x + len * mx[t],y + len * my[t],k - 1);
          if (best > tmp)
          {
             best = tmp;  p0[x][y][k] = i;  p1[x][y][k] = j;
          };
      };

    f[x][y][k] = best;  return best;
};

void track(int x,int y,int k)
{
     if (!k)
     {
        fin[x][y] = a[x][y];  return;
     };
     int pos = p1[x][y][k],len = 1 << (k - 1);
     for (int i = x + len * mx[pos]; i < x + len * mx[pos] + len; i++)
       for (int j = y + len * my[pos]; j < y + len * my[pos] + len; j++) fin[i][j] = 1;
     for (int t = 0; t < 4; t++) if (t != p0[x][y][k] && t != p1[x][y][k]) track(x + len * mx[t],y + len * my[t],k - 1);
};

int main()
{
//    freopen("slikar.in","r",stdin);
//    freopen("slikar.ou","w",stdout);
    scanf("%d", &n);
    for (int i = 1; i <= n; i++)
      for (int j = 1; j <= n; j++)
      {
          char ch;
          while (1)
          {
                scanf("%c", &ch);
                if (ch == '0' || ch == '1') break;
          };
          a[i][j] = ch - '0';
      };

/*    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= n; j++) cout << a[i][j];
        cout << endl;
    };*/

    memset(b,0,sizeof(b));    
    for (int i = 1; i <= n; i++)
      for (int j = 1; j <= n; j++) b[i][j] = a[i][j];
    for (int i = 2; i <= n; i++)
      for (int j = 1; j <= n; j++) b[i][j] += b[i - 1][j];
    for (int i = 1; i <= n; i++)
      for (int j = 2; j <= n; j++) b[i][j] += b[i][j - 1];

    memset(f,-1,sizeof(f));
    int tmp = n,k = 0;  
    while (tmp > 1)
    {
          tmp /= 2;  k++;
    };

    int ret = rec(1,1,k);
    memset(fin,0,sizeof(fin));
    track(1,1,k);
    printf("%d\n", ret);
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= n; j++) printf("%d", fin[i][j]);
        printf("\n");
    };
};

Code mẫu của khuc_tuan

// {$APPTYPE CONSOLE}
 {$mode delphi}

uses math, sysutils;

const
    dx : array[1..4] of integer = (0,0,1,1);
    dy : array[1..4] of integer = (0,1,0,1);

type
    Data = class
        b, w, r : integer;
    end;

var
    n, i, j : integer;
    a, b : array[1..555,1..555] of char;

procedure fill(sx, sy, len : integer; c : char);
var
    i, j : integer;
begin
    for i:= sx to sx + len - 1 do
        for j:= sy to sy + len - 1 do
            b[i,j] := c;
end;

function color(sx, sy, len : integer) : Data;
var
    res : Data;
    kq : array[1..4] of Data;
    cur, best, btr, bde, tr, de, i, j, z : integer;
begin
    res := Data.Create;

    for i:=sx to sx + len - 1 do
        for j:=sy to sy + len - 1 do
            if a[i,j]='0' then inc(res.b)
            else inc(res.w);

    if len = 1 then
    begin
        b[sx,sy] := a[sx,sy];
        // if b[sx,sy] <> a[sx,sy] then inc(res.r);
        color := res;
        exit;
    end;

    z := len div 2;

    for i:=1 to 4 do
        kq[i] := color( sx + dx[i] * z, sy + dy[i] * z, z);

    best := 1000000000;

    for tr := 1 to 4 do
        for de := 1 to 4 do if de <> tr then
        begin
            cur := kq[tr].w + kq[de].b;
            for i := 1 to 4 do if (i<>de) and (i<>tr) then cur := cur + kq[i].r;
            if cur < best then
            begin
                best := cur;
                btr := tr;
                bde := de;
            end;
        end;

    fill( sx + dx[btr] * z, sy + dy[btr] * z, z, '0');
    fill( sx + dx[bde] * z, sy + dy[bde] * z, z, '1');

    res.r := best;
    color := res;
end;


begin
    readln(n);
    for i:=1 to n do
    begin
        for j:=1 to n do read(a[i,j]);
        readln;
    end;

        writeln(color(1, 1, n).r);
        for i:=1 to n do
        begin
            for j:=1 to n do
                write(b[i,j]);
            writeln;
        end;
end.