Олимпиада по информатике для школьников

 var s:string;
     c:char;
begin
 assign(input,'input.txt');
 reset(input);
 assign(output,'output.txt');
 rewrite(output);
 s:='';
 while not eof(input) do begin
  read(c);
  if c in ['A'..'Z','a'..'z'] then s:=c+s
  else begin
   write(s);
   s:='';
   write(c);
  end;
 end;
 write(s);
 close(input);
 close(output);
end.

<?php  
$input = file_get_contents('input.txt');
$search = "/([a-zA-Z]*)([^a-zA-Z]*)/";
preg_match_all($search, $input, $s);
array_walk($s[1], create_function('&$v', '$v = strrev($v);'));
$s = array_map(create_function('$x,$y', 'return $x.$y;'), $s[1], $s[2]);
$output = implode('',$s);
file_put_contents('output.txt', $output);
?>

var rows,cols:integer;
      a:array[1..10,1..10] of integer;

function calc(row,col:integer):longint;
  var down,right,max:longint;
 begin
  calc:=0;
  if (row>rows) or (col>cols) then exit;
  down:=calc(row+1,col);
  right:=calc(row,col+1);
  if down>right then max:=down
  else max:=right;
  calc:=a[row,col]+max;
 end;

 var i,k:integer;
begin
 assign(input,'input.txt'); reset(input);
 assign(output,'output.txt'); rewrite(output);
 readln(rows,cols);
 for i:=1 to rows do begin for k:=1 to cols do read(a[i,k]); readln; end;
 writeln(calc(1,1));
 close(input); close(output);
end.

var a1,a2,a3,b1,b2,b3,c1,c2,c3:double;
    x1,x2,x3,y1,y2,y3:double;
    vx1,vy1,vx2,vy2,delta:double;
begin
 assign(input,'input.txt');
 reset(input);
 assign(output,'output.txt');
 rewrite(output);
 read(a1,b1,c1,a2,b2,c2,a3,b3,c3);
 close(input);
  delta:=a1*b2-a2*b1;
  x1:=(c1*b2-c2*b1)/delta;
  y1:=(a1*c2-a2*c1)/delta;

  delta:=a2*b3-a3*b2;
  x2:=(c2*b3-c3*b2)/delta;
  y2:=(a2*c3-a3*c2)/delta;

  delta:=a1*b3-a3*b1;
  x3:=(c1*b3-c3*b1)/delta;
  y3:=(a1*c3-a3*c1)/delta;

  vx1:=x2-x1;
  vy1:=y2-y1;
  vx2:=x3-x1;
  vy2:=y3-y1;
  
  writeln(abs((vx2*vy1-vx1*vy2)/2):0:3);

 close(output);
end.

const mas:array[0..9,1..3] of integer=(
(4,6,-1),(6,8,-1),(7,9,-1),
(4,8,-1),(3,9,0),(-1,-1,-1),
(1,7,0),(2,6,-1),(1,3,-1),(2,4,-1));

var N,tel:integer;

procedure find(digit,count:integer);
  var i:integer;
 begin
  if digit=-1 then exit;
  if count=7 then begin inc(tel); exit end;
  for i:=1 to 3 do find(mas[digit,i],count+1);
 end;

begin
 assign(input,'input.txt'); reset(input);
 assign(output,'output.txt'); rewrite(output);
 readln(N);
 find(n,1);
 writeln(tel);
 close(input); close(output);
end.