1. Input: 7122 2119
2. Input: 7122 2120

program p1071;
var x,y,z,s,i:longint;
    out:boolean;
procedure check(p:longint);
var  x1,y1:longint;
     c:array[0..10000] of integer;
begin
     fillchar(c,sizeof(c),0);
     x1:=x;y1:=y;
     repeat
           inc(c[x1 mod p]);
           x1:=x1 div p;
     until x1=0;
     repeat
           if c[y1 mod p]>0 then dec(c[y1 mod p])
                            else exit;
           y1:=y1 div p;
     until y1=0;
     out:=true;
end;
begin
     readln(x,y);z:=0;out:=false;
     for i:=2 to x do
         if x mod i=y mod i then
         begin
              check(i);
              if out then break;
         end;
     if out then write(i)
            else write('No solution');
     readln;
end.

what test 4 looks like?

I Solved this problem, by transforming x and y into every system and search for the longest common substring.
But I am interested in another Ideas, better than mine, except brute force.

3 2

I basically used brute force,

if ( x==y) cout<<2;
if (x < y) cout<<"No solution";

then the rest brute force

Please give me some tests.

var x,y,x1,y1,f,l:longint;a,b,c:array[1..1000] of byte;
   i,k,s,r,w,z:word;
begin
read(x, y);
l:=2;w:=0;
While (f<>1)and(l<=10) do begin
i:=1;
x1:=x;
s:=0;
c:=a;
b:=a;

Repeat
c[i]:=x1 mod l;
x1:=x1 div l;
inc(i);
inc(s)
until x1=0;

y1:=y;k:=0;
i:=1;
Repeat
b[i]:=y1 mod l;
y1:=y1 div l;
inc(i);
inc(k)
until y1=0;

r:=b[k];z:=1;i:=s;

Repeat
If c[i]=r then begin r:=b[k-z];inc(z);end;
dec(i);
until (z=k+1)or(i=0);
If z=k+1 then begin f:=1;w:=l;end;
inc(l);
end;
If w=0 then writeln('No solution')
else writeln(w)


end.

Help me please...

The best way to solve this problem is with bruteforce...
My brute: 0.031 121KB :)

New tests have been added. 15 authors have lost AC.

I WAS one of the ACers in this problem.
I thought my algo was correct until...
Can U tell me some tests to find out my mistake(s)?

New tests were added. 169 authors lost AC.

200
3
100
100
100

Is it -1?

Edited by author 13.06.2006 11:57

How is it possible? There are really power server!

program de;
   var
   a,n,i,r,x,y,step,j:longint;
   q:boolean;
   s1,s2,s:string;
begin
  step:=1;
  q:=false;
  read(x);
  read(y);
  repeat
    s1:='';
    s2:='';
    n:=x;
    inc(step);
    repeat
     i:=n mod step;
     n:=n div step;
     str(i,s);
     s1:=s+s1;
    until n=0;
    r:=y;
    repeat
     i:=r mod step;
     r:=r div step;
     str(i,s);
     s2:=s+s2;
    until r=0;
    j:=1;
    for i:=1 to length(s1) do
     if (s1[i]=s2[j]) and (j<>length(s2)+1) then inc(j);
    if j=length(s2)+1 then q:=true;
  until (step=x+1) or q;
  if q then writeln(step)
  else writeln('No solution');
end.

program de;
   var
   a,n,i,r,x,y,step,j:longint;
   q:boolean;
   s1,s2,s:string;
begin
  step:=1;
  q:=false;
  read(x);
  read(y);
  repeat
  s1:='';
  s2:='';
  n:=x;
  inc(step);
  repeat
  i:=n mod step;
  n:=n div step;
  str(i,s);
  s1:=s+s1;
  until n=0;
  r:=y;
  repeat
  i:=r mod step;
  r:=r div step;
  str(i,s);
  s2:=s+s2;
  until r=0;
  j:=1;
  for i:=1 to length(s1) do
  if (s1[i]=s2[j]) and (j<>length(s2)+1) then inc(j);
  if j=length(s2)+1 then q:=true;
  until (step=x+1) or q;
  if q then writeln(step)
  else writeln('No solution');
end.